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UNITED STATES OF AMERICA. 



A SHORT COURSE 



CHEMISTRY, 



BASED ON THE 



EXPERIMENTAL METHOD. 



BY 

y 

THOMAS R. BAKER, Ph.D., 



Professor of Physics and Chemistry, State Normal School, 

MlLLERSVILLE, Pa. ; AND AUTHOR OF ELEMENTS OF 

Natural Philosophy. 



<-A 






s0m 




LANCASTER, PA.: 

Normal Publishing Company. 

1883. 



BY THE AUTHOR OF THIS WORK. 

ELEMENTS OF NATURAL PHILOSOPHY. 

Retail price, §1.50. 

Published by PORTER & COATES, 

Philadelphia. 

A SHORT COURSE IN CHEMISTRY. 
Retail price, §1.00. 

Copyright, 1883, By THOMAS R. BAKER. 



INQUIRER P. & P. CO.. 

STEREOTYPERS AND PRINTERS, 

LANCASTER, PA. 



«£> 



X^ 



PREFACE. 



The study of Chemistry is valuable for the reason that the 
science directs attention to many important facts and phe- 
nomena of nature and contributes greatly to the comforts and 
conveniences of life. It is also valuable as a means of educa- 
tion, affording in a high degree — if the subjact be rightly pur- 
sued — the special culture needed for general scientific work. 

This volume is designed for students beginning the subject 
of chemistry. It presents the leading facts and principles of 
the science, including the results of the most recent chemical 
study and investigation, and may therefore serve either for 
class instruction or for private students. The arrangement of 
the subject matter and the order of discussion are natural and 
logical, and will enable the student easily to study the subject 
and readily to remember what he has learned. To render the 
study more intelligible, the general subject is preceded by a 
discussion of chemical nomenclature and notation, and of the 
more important chemical terms and processes. To facilitate 
the experimental work directed by the book, the experiments 
are described in careful detail, and are generally preceded by 
an enumeration of the apparatus and material needed in per- 
forming them. 

In the preparation of the book the author has freely con- 
sulted the admirable works of Bloxam, Fowne, Cooke, Pinner 
and others. He acknowledges his indebtedness to Prof. A. A. 
Breneman for valuable assistance in the classification of the 
subject, etc., and to Prof. E. Oram Lyte, for valuable sugges- 
tions relating to the typography of the work. His thanks are 
also due to Messrs. Bullock & Crenshaw, 528 Arch St., Phila- 
delphia, and to Messrs. Queen & Co., 924 Chestnut St., Phil- 
adelphia, for cuts of apparatus described in the appendix. 

State Normal School, 

Millersville, Pa., July, 1883. 

(3) 



SUGGESTIONS TO TEACHERS AND PUPILS. 



This book is designed to combine both theoretical and experimental 
instruction. An experiment should first be described by the pupil and 
then performed before the class, either by the teacher or by a pupil under 
the direction of the teacher. Or the entire lesson may be recited, and 
then the pupils, provided with their own apparatus and places at a 
laboratory table, be assigned the experiments to perform for themselves. 
They may be assigned the same experiment or different experiments, ac- 
cording to the number contained in the lesson. The book may be used 
in the class-room without performing the experiments, but this plan is 
not a good one. Or it may be used as a laboratory text-book, the stu- 
dent carefully reading the theoretical part. 

If the teacher is not provided with a chemical laboratory, there should 
be a room set apart, near the class-room if possible, for chemical manip- 
ulation. This room should be capable of easy and thorough ventilation, 
and should contain a chimney or flue to carry off offensive and noxious 
gasea and vapors. If regular laboratory tables (which are large tables 
supporting shelves for reagents, etc., with drawers and cupboards under- 
neath) cannot be obtained, almost any tables will answer the purpose. 

The pupil should keep his apparatus and his part of the table clean, 
and learn to work neatly. He should carefully observe the results of 
experiments and clearly understand how these results establish the facts 
stated. If an experiment fails, it should be tried again, and the cause 
of the failure carefully studied. 

(4) 



P 



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CONTENTS. 



PAGE. 

INTRODUCTION. 

Historical Sketch. Definitions. Properties of Matter. 
Chemical Elements and Compounds. Chemical Affinity 
and Chemical Action. Nomenclature and Notation. Chem- 
ical Terms. Chemical Processes 7-22 

INORGANIC CHEMISTRY. 

Hydrogen 23-28 

Sodium Group. — Sodium. Potassium. Lithium. Rubidium. 

Cassium. Silver 29-37 

Chlorine Group. — Chlorine. Bromine. Iodine. Fluorine . 38-45 
Oxygen Group. — Oxygen. Sulphur. Selenium. Tellurium . 45-57 
Calcium Group. — Calcium. Barium. Strontium. Lead . 58-62 
Magnesium Group. — Magnesium. Zinc. Cadmium . . . 62-64 
Aluminum Group. — Aluminum. Indium. Gallium. Cer- 
ium. Didymium. Lanthanium 64-66 

Copper Group. — Copper. Mercury 66-69 

Nitrogen Group. — Nitrogen. Phosphorus. Arsenic. Anti- 
mony. Bismuth. Vanadium. Uranium. Columbium. 

Tantalum 69-83 

Gold Group.— Gold. Boron. Thallium 83-85 

Iron Group. — Iron. Manganese. Nickel. Cobalt . . . 85-91 
Chromium Group. — Chromium. Molybdenum. Tungsten . 91 
Platinum Group. — Platinum. Iridium. Osmium. Pal- 
ladium. Rhodium. Ruthenium 91-92 

Carbon Group. — Carbon. Silicon. Tin. Zirconium . . 92-106 

ORGANIC CHEMISTRY. 

Hydrocarbons and Derivatives. — Paraffines. Olefines. Aro- 
matic Compounds. Camphors. Resins. Alcohols. 
Ethers. Aldehydes and Acids 107-113 

(5) 



6 CONTENTS. 

PAGE. 

Carbyhydrates. — Sugars. Starch. Cellulose. Gums . . 113-117 
Acids. — Acetic. Oxalic. Tartaric. Citric. Malic. Tan- 
nic. Salicylic 117-120 

Alkaloids 120 

Albuminoids 120-121 

Fats and Fixed Oils 121-122 

Coloring Substances 123-124 

QUESTIONS 125 

APPENDIX. 

Balance and Weights. Metric Measures. Thermometers. 
Lamps. Blowpipes. Blowers. Pneumatic Trough. Gas- 
holders. Compressors and Pincettes. Retort Stand and 
Other Supports. Filtering Apparatus. Stoppers. Cork- 
Borers. Mortars, Evaporators, Crucibles. Glass Appa- 
ratus. Glass and Rubber Tubing. Litmus Paper. Glass- 
Working 132-147 



A SHORT COURSE 

IN 

CHEMISTKT. 



I 



INTRODUCTION. 

Historical Sketch. 

T is supposed that the Egyptians possessed the most chem- 
ical knowledge of any nation of antiquity. They could 
preserve the bodies of their dead, were skilled in the art 
of dyeing, and could prepare many chemical products, 
among which were various medicines, soap, and glass. It is 
probable that the term chemistry is derived from the ancient 
name for Egypt, Chemia. 

The Chinese, at a very early date, were acquainted with the 
preparation of gunpowder, the making of paper, etc. The 
Greeks and Romans gained most of their chemical knowledge 
from the Egyptians, and made little advancement in the sci- 
ence. Aristotle held that there are four elementary sub- 
stances, fire, air, earth, and water. 

In the Middle Ages the impression prevailed that there ex- 
isted a substance called the "philosopher's stone," which could 
change all things into gold, and this substance was eagerly 
sought after by the chemists of the time, called alchemists. 
The alchemist's work embraced also the search for the " elixir 
of life " by which existence could be indefinitely prolonged. 

The discovery of aqua regia, the solvent of gold, the expla- 
nation of the action of acids and bases, and the investigation of 
the causes of chemical action and the chemical relations of 
• (?) 



8 PROPERTIES OF MATTER. 

heat and light, were important steps in the direction of mod- 
ern chemistry, which may be said to have originated toward 
the end of the 17th century. It was then that oxygen was 
discovered, the chemical knowledge of the time systematized 
by Lavoisier, and the atomic theory introduced by Dalton. 
The researches of Davy, Gay Lussac, Faraday, Wohler, 
Liebig, and many distinguished men of our own time, have 
brought the science to its present advanced condition. 

Definitions. 

Matter is anything that occupies space, as earth, water, air. 

Units of Matter. — An atom is an ultimate, indivisible 
portion of matter. The atomic theory assumes that all matter 
is made up of atoms, that the atoms of the same element have 
a uniform weight, and that the atoms of different elements 
have different weights. A molecule is a combination of atoms. 
A mass is an aggregation of molecules, and the term is applied 
to the motes in air as well as to rocks and worlds. The term 
mass is also used to denote the quantity of matter in a body. 

A Substance is one of the kinds of matter, as gold, wood, 
oil. Organic substances are those that are produced by life; 
inorganic substances are those that are not produced by life. 
Tallow and wood are organic ; iron and water, inorganic. 

JProjjerties of 3Iatter. 

Physical properties arise from physical changes, which change 
the form and quality of a substance without destroying its 
distinctive character. Thus iron may be made into a multi- 
titude of useful articles, but its nature is not changed. Ice 
and steam are only forms of water. 

Chemical properties arise from chemical changes which de- 
stroy the distinctive character of a substance. Thus the 
products obtained by decomposing water, oxygen and hydro- 
gen, are entirely unlike water. When limestone is burned, its 
carbonic acid is driven off and lime is left. 

Chemistry treats of the kinds and properties of matter, and the 
chemical changes which it undergoes. 



INTRODUCTION. 9 

Chemical Elements and Compounds. 

A Chemical Element or simple substance is a substance that 
cannot be separated into different kinds of matter. Thus 
iron and sulphur are elements, because they cannot be sepa- 
rated into parts which are not iron and sulphur. 

A Chemical Compound is a substance formed of elements 
united chemically ; as, water (II and O), sugar (C, H, and O). 
Compounds are classified as binary, composed of two elements, 
ternary, composed of three elements, etc. 

Acids, Bases, and Salts. — The most important ternary 
compounds are acids, bases, and salts. An acid is a compound 
generally soluble in water and having usually a sour taste. 
The acids all contain H, generally O, and another element. 
A base is a hydrate (p. 17) which has the power of neutraliz- 
ing an acid. A salt (so named from its resemblance to com- 
mon salt) is a compound formed by the replacing of the H 
of an acid by a metal or electro-positive radical. (See the 
author's Nat Phil., p. 285.) 

A Radical is an atom or a group of atoms forming the chief 
constituent of the molecule of a compound. A simple radical 
is composed of a single atom ; a compound radical is com- 
posed of a group of atoms. The group acts as a single atom. 

Analysis and Synthesis. — Chemical analysis is the pro- 
cess of separating a compound into its constituent parts. 
When the parts are elements, the process is called ultimate 
analysis; when they are compounds, it is called proximate 
analysis. Synthesis is the union of substances to form a new 
compound. 

A Mixture is a product formed of substances not united 
chemically ; as, air (O, N, etc.), gunpowder (charcoal, sulphur, 
saltpetre). The parts of a mixture may be separated by 
mechanical means ; the elements of a compound cannot thus 
be separated. Thus iron filings and flowers of sulphur, when 
mixed together, may be separated by means of a magnet, but 
if the mixture be strongly heated, the ingredients combine 
chemically and they cannot be thus separated. 



10 



TABLE OF THE ELEMENTS. 
Table of the Elements. 



(S.=symbol; At. Wt.=Atomic Weight. Names op least important 
Elements in Italics.) 



Name. 


S. 


At. 

Wt. 


Derivation. 


Discovery. 


Aluminum . . . 


Al . 


27-0 


Lat. alumen, alum . . . 


Wohler, 1828. 


Antimony {stib- 




120-0 






ium) 


Sb . 




Arab, al-ithmidan . . . 


Valentine, 1640? 


Arsenic 


As . 


75-0 


Gr. arsenicon 


Schroeder, 1694. 


Barium .... 


Ba . 


137-1 


Gr. baros, heavy .... 


Davy, 1808. 


Bismuth .... 


Bi. . 


210.0 


Ger. wesemat 


Agricola, 1529. 


Boron 


B . . 


11-0 


Arab, bur ay, borax . . . 


Davy, 1807. 


Bromine .... 


Br . 


80-0 


Gr. bromos, stench . . . 


Balard, 1826. 


Cadmium ... 


Cd . 


112-3 


Gr. cadmia, calamine . . 


Stromeyer, 1817. 


Caesium .... 


Cs . 


133-0 


Lat. caesius, blue. . . . 


Bunsen, 1860. 


Calcium .... 


Ca . 


40-0 


Lat. calx, lime 


Davy, 1808. 


Carbon 


C. . 


12-0 


Lat. carbo, coal .... 


Ancients. 


Cerium 


Ce . 


141-0 


Lat. Ceres, a Roman deity. 


Berzelius, Hisin- 
ger, 1803. 


Chlorine .... 


CI. . 


35-5 


Gr. chloros, green . . . 


Scheele, 1774. 


Chromium . . . 


Cr . 


52-2 


Gr. chroma, color . . . 


Vanqueliu, 1797. 


Cobalt 


Co . 


58-8 


Ger. kobold, a goblin . . 


Brandt, 1733. 


Columbium . . . 


Cb . 


94-0 


Columbia, America . . . 


Hatchett, 1801. 


Copper (cuprum) . 


Cu . 


63-3 


Lat. cyprium, Cyprus . . 


Ancients. 


Decipium (?) . . 


De . 


157-0 


Lat. decipere, to deceive . 


Delafontaine, '78. 


Didymium. . . . 


D. . 


140-0 


Gr. didumos, double . . 


Mosander, 1841. 


Erbium 


Er . 


167-0 


Ytterby in Sweden . . . 


Mosander, 1843. 


Fluorine .... 


F . . 


19-1 


Lat. Jluere, to flow . . . 


Not isolated. 


Gallium 


Ga . 


70-0 


Lat. Gallia, France. . . 


Boisbaudran, '77. 


Gludnum .... 


Gl . 




Gr. glukus, sweet. . . . 


Vanquelin, 1798. 


Gold (aurum) . . 


Au . 


197-0 




Ancients, 


Holmium (?). . . 


Ho 


162-0 


Stockholm 


Cleve, 1879. 


Hydrogen .... 


H. . 


1 . . 


Gr. hudor, water, and gen- 
ein, to produce .... 


Cavendish, 1766. 


Indium 


In. . 


113-7 


Indigo, a blue dye . . . 


Reich, Richter, 
1863. 


Iodine 


I . . 


126-8 


Gr. ion, violet 


Courtois, 1811. 


Iridium . ... 


Ir. . 


192-7 


Lat. iris, rainbow . . . 


Tennant, 1803. 


Iron (ferrum) . . 


Fe . 


56-0 




Ancients. 


Lanthanum . . . 


La . 


139-0 


Gr. lanthanein, to conceal. 


Mosander, 1841. 


Lead (plumbum) . 
Lithium 


Pb . 

Li. . 


206-9 

7-0 




Ancients. 


Gr. lithos, a stone . . . 


Davy, Arvedson, 










1818. 


Magnesium . . . 


Mg. 


24-0 


Magnesia, Asia Minor . . 


Bussy, 1830. 


Manganese . . . 


Mn . 


55-0 


" " " . . 


Galm, 1774. 


Mercury (hydrar- 










gyrum) .... 


Hg. 


200-0 


Name of Roman deity . 


Ancients. 


Molybdenum . . . 


Mo . 


96-0 


Gr. molybdos, lead . . . 


Hjelm, 1782. 


Nickel 


Ni . 


58-6 


Ger. kup/ernickel .... 


Cronstedt, 1751. 



INTRODUCTION. 



11 



Name. 


S. 


At. 
Wt. 


Derivation. 


Discovery. 


Nitrogen .... 


N. . 


14-0 


Gr. nitron, nitre, and ^re- 


Rutherford, 1772. 


Norwegium (?). . 


No . 


145-9 


Norway 


Dahll, 1879. 


Osmium 


Os . 


199-2 


Gr. osme, odor 


Tennant, 1803. 


Oxygen 


0. . 


16-0 


Gr. ozus, acid, and genein. 


Priestley, 1774. 


Palladium. . . . 


Pd . 


106-6 


Gr. Pallas, a deity . . . 


Wollaston, 1804. 


Phosphorus . . . 


P . . 


31-0 


Gr. phos and phero . . . 


Brandt. 1669. 


Platinum .... 


Pt . 


194-8 


Spa,n. platina 


Wood, 1741. 


Potassium (kal- 










ium) 


K. . 


39-1 


Eng. pot-ashes 


Davy, 1807. 


Rhodium .... 


Rh . 


104-4 


Gr. rhodon, a rose . . . 


Wollaston, 1803. 


Rubidium .... 


Jib . 


85-4 


Lat. rubidus, red .... 


Bunsen, 1860. 


Ruthenum .... 


Ru . 


104-4 


Ruthenia, Russia .... 


Claus, 1845. 


Scandium .... 


Sc . 


44-0 


Scandinavia (?) .... 


Nilson, 1879. 


Selenium .... 


Se . 


79-2 


Gr. selene, the- moon . . 


Berzelius, 1817. 


Silicon 


Si . 


28-0 


Lat. silex, flint 


Berzelius, 1823. 


Silver (argentum). 
Sodium {natrium) 


Ag, 

Na* 


108-0 
23-0 




Ancients. 


Lat. salsola, soda. . . . 


Davy, 1807. 


Strontium .... 


Sr. . 


87 - 6 Strontian, Scotland. . . 


Davy, 1807. 


Sulphur .... 


S . . 


32-0 


Lat. sulfur 


Ancients. 


Tantalum .... 


Ta . 


182-0 


Tantalus, mythol. person. 


Ekeberg, 1802. 


Tellurium .... 


Te . 


128-0 


Lat. tellus, the earth . . 


Klaproth, 1798. 


Terbium (?) . . . 


Tr . 


m-o 


Lat. ter, third . . . 


Mosander, 1843. 


Thallium .... 


Tl . 


204-1 


Gr. thallos, a green twig. 


Crookes, 1861. 


Thorium .... 


Th . 


231-4 


Thor, a Swedish deity . 


Berzelius, 1829. 


Thulium (?) . . . 


Tm . 


170-0 


Lat. Thule 


Cleve, 1879. 


Tin (st annum) . . 


Sn . 


118-0 




Ancients. 


Titanium .... 


Ti. . 


50-0 


Titans, mythol. person . 


Klaproth, 1791. 


Tungsten ( Wolf- 










ramium) . . . 


Wo. 


184-0 


Sw. heavy stone .... 


De Luyart. 


Uranium .... 


Ur . 


120-0 


Gr. Ouranos, heaven. . . 


Klaproth, 1789. 


Vanadium. . . . 


V. . 


51-3 


Vanadis, deity 


Lefstrom, 1830. 


Ytterbium (?) . . 


Yb . 


173-0 


Ytterby in Sweden. 




Yttrium 


Y. . 


91-0 


Ytterby 


Wohler, 1828. 


Zinc 


Zn . 


65-2 




Paracelsus. 


Zirconium .... 


Zr . 


89-6 


Ceylonese, Zircon . . . 


Berzelius, 1824. 



Substances which will generally be designated by their symbols. 



Oxygen O. 

Hydrogen H. 

Nitrogen N. 

Chlorine CI. 

Sulphur S. 

Carbon C. 



Water H 2 0. 

Hydrochloric Acid HC1. 

Sulphuric Acid H 2 S0 4 . 

Nitric Acid HN0 3 . 

Ammonium Hydrate . . (NH 4 )HO. 
Carbon Dioxide(Carbonic Acid)CO r 



12 NOMENCLATURE AND NOTATION 

Chemical Affinity and Chemical Action. 

Chemical Affinity or Chemism, is the force by means of which 
elements combine to form chemical compounds ; as O and 
iron to form iron rust. It acts between atoms, and hence at 
insensible distances. It is variously affected by cohesion, heat, 
light, and electricity. 

Chemical Action is the action due to chemical union and 
separation. It may be energetic, as in the burning of gun- 
powder, or quiet, as in the rusting of iron. 

Nomenclature and Notation, 

Symbols are used in chemistry to represent substances more 
briefly than they are represented by the name, and also to 
designate their atomic constitution, the symbol of an element 
designating a single atom. 

Elements. 

Names. — The elements which were earliest known retain 
their old names. Many of those more recently discovered 
are named from some property; as, chlorine, from its green 
color, and bromine, from its fetid odor. The names of the 
recently discovered metals end in um; as, sodium, potassium. 

Symbols. — The initial letter of the Latin name of an ele- 
ment is generally taken as the symbol of the element. When 
two or more names have the same initial letter, a second letter 
is added. Thus O is the symbol of oxygen, C of carbon, Ca 
of calcium, and CI of chlorine. 

General Compounds. 

'Names. — Chemical compounds have names which desig- 
nate their ingredients, and generally at least one other name 
by which they are known in commerce. Thus hydrochloric 
acid (composed of H and CI) is also called muriatic acid. 

Symbols. — The symbol of a compound is formed of the 
symbols of its constituent elements, generally arranged in the 
order in which they occur in the name of the compound. 
Thus HC1 is the symbol of hydrochloric acid. 



INTR D UCTION. 1 3 

A small figure on the line at the right of a symbol denotes 
the number of atoms when more than one are combined. 
Thus Ho (read H-two) means two atoms of H. A figure to 
the left of a symbol or group of symbols, from which it is not 
separated by a parenthesis, multiplies the symbol or group. 
Thus 3 H 2 means three molecules of water. A figure out- 
side of a parenthesis multiplies the group or groups within the 
parenthesis. Thus 2 (NH 4 C1) or (NH 4 C1) 2 means two mole- 
cules of ammonium chloride. 

The results of chemical reactions are expressed by equa- 
tions. The symbols of the substances to be acted on are 
placed as the left-hand member and those of the new product 
or products as the right-hand member of the equation. Thus: 

CaO + H 2 = Ca0 2 H 2 

Lime Water Calcium hydrate. 

The term formula is sometimes applied to the symbols of a 
compound. When the symbols are arranged so as to indicate 
the substances which have combined to produce the compound, 
they constitute a rational formula ; when they represent the 
composition of the compound only, they constitute an empirical 
formula. Thus the rational formula of ordinary phosphoric 
acid is 3 H 2 0,P 2 5 (H 2 0, and phosphoric oxide) ; the empirical 
formula is H 3 P0 4 (similar in the proportion of the atoms in- 
dicated to 3 H 2 0,P 2 5 ). 

Classified Compounds. 

Binaries. — The name of a binary , is formed from the 
names of both elements. The first part of the name is that 
of the most electro-positive element with the termination 
changed to ous or ic, the second expressing the larger quantity 
of the positive element. The second part of the name is that 
of the most electro-negative element with the termination 
changed to ide. Thus ferrous oxide (FeO), ferric oxide 
(Fe 2 3 ). The latter contains the most O. 

Prefixes are also used and are either numeral, as in the term 
dioxide (two atoms of O), or general, as in perchloric and 



14 LAWS OF CHEMICAL COMBINATION. 

hypochloric, which are used when more than two compounds 
are formed of two elements. 

Ternaries. — In naming the inorganic acids and the bases 
(hydrates), the terminations oils and ic are used as in naming 
binaries. Thus, sulphurous acid, H 2 S0 3 , sulphuric acid, 
H 2 S0 4 , ferrous hydrate, FeH 2 2 , ferric hydrate, Fe 2 H 6 6 . 

In naming the salts the name of the group or class is formed 
by changing the ous terminating the name of the acid to ite 
or the ic to ate. Thus sulphurous acid forms a sulphite, and 
sulphuric acid, a sulphate. 

Bond and Graphic Symbols. 

Bond Symbols are the ordinary symbols with short lines 
called bonds, indicating the quantivalence (p. 15) of the' ele- 
ment, radiating from them. Thus : (p. 16). 

Monad, Dvad, Triad, Tetrad, Pentad, Hexad. 

H- 0= X_ C= =--Pi= -Fe- 

The bonds may have almost any direction, as 0=, -0-, 

6-, O < etc. 

When chemical action takes place the bonds are united, 
each atom having the number by which it is designated. 
Thus : 

H 

H H-C-H 

H-Cl H-O-H H-N-H H 

Hydrochloric Acid, Water, Ammonia, Marsh Gas. 

Graphic Symbols are diagrams used as symbols. Those de- 
vised by Kekule consist of short dashes, enclosed by curves, 
to indicate the quantivalence of the atom. Thus H is repre- 
sented by one enclosed dash, O by two enclosed dashes, etc. 

Laws of Chemical Combination. 

Definite Proportions. 
A chemical compound always contains the same elements com- 
bined in the same proportions. Thus, pure H 2 is composed of 
11.11 parts by weight of H to 88.89 parts of O; HC1, 2.74 
parts of H to 97.26 of CI. 



INTRODUCTION. 15 

Atomic Weights, — The molecule of H 2 consists of two 
atoms of H and one of O. Hence, referring to the composi- 
tion of HoO just given, the atom must be 16 times as heavy 
as the H atom. It is also seen that the CI atom is 35.5 times 
as heavy as the H atom. The numbers 1, 16, 35.5, are called 
atomic weights (p. 10). 

The atomic weights of the elements are therefore the rela- 
tive weights of their atoms. The absolute weight of the atoms 
cannot be determined. 

The molecular iveight is equal to the sum of the weights of 
the atoms in the molecule. Thus the molecular weight of 
H 2 is 18. 

Percentage Composition. — The part which an element 
forms of a compound is indicated by the ratio of the atomic 
weight of the element to the molecular weight of the com- 
pound. Thus, since the molecular weight of H 2 is 18 

H O 

(2 -j- 16), the H forms T \ or 11.11 per cent., and the O, if or 
88.89 per cent. 

Multiple Proportions. 
If more than one compound is formed by the union of two ele- 
ments, the larger quantities of the combining elements are simple 
multiples of the smallest quantity. A good illustration of this 
law is afforded by the compounds of O and N, shown in the 
following table. The amount of O which is combined in each 
with 1.75 parts of N, is given. 

N NO 

By Weight. By Weight. By Vol. By V61. 
Nitrogen Monoxide, N 2 . 1.75 . . . 1 . . . 2 . . .1 
Nitrogen Dioxide, NO . . 1.75 ...2. ..2. ..2 
Nitrogen Trioxide, N 2 3 . . 1.75 . . . 3 . . 2 ... 3 
Nitrogen Tetroxide, N0 2 . 1.75 . . . 4 . . . 2 . . .4 
Nitrogen Pentoxide, N 2 5 . 1.75 . . .5. . .2. . .5 

QUANTIVALENCE. 

One atom of CI unites with one of H to form HC1 ; one of 
O unites with two of H to form H 2 ; one of N unites with 



10 VOLUME RELATIONS. 

three of H to form ammonia ; one of C unites with four of H 
to form marsh gas. It is thus seen that the different kinds of 
atoms, CI, O, etc., require different numbers of H atoms with 
which to form compounds. 

HC1 H 2 H 3 X H 4 N 

Hydrochloric Acid. Water Ammonia. Marsh Gas. 

One atom of potassium replaces one of H in HN0 3 to form 
potassium nitrate ; one of copper replaces two of H in H 2 S0 4 
to form copper sulphate. 

H|X0 3 , Nitric Acid, H 2 jS0 4 , Sulphuric Acid. 

K|N0 8 , Potassium Nitrate, Cu |S0 4 , Copper Sulphate. 

This quantity-combining or quantity-replacing power of an 
element is called its quantivalence, and the H atom is taken 
as the standard of reference. 

It may therefore be stated that the quantivalence of an ele- 
ment or of a compound radical denotes the number of hydrogen 
atoms with which one of its atoms can combine or the number of 
hydrogen atoms which one of its atoms can replace. Thus the 
quantivalence of potassium is 1, of oxygen 2, of carbon, 4. 

The elements are classified according to their quantivalence 
as monads, dyads, triads, etc., potassium being a monad, oxy- 
gen, a dyad, and carbon, a tetrad. 

Volume Relations. 

A mpere's Law. — The following, called Ampere's Law, is 
accepted as a fundamental principle of chemistry: Equal vol- 
umes of all gases, under like conditions of temperature and pres- 
sure, contain the same number of molecules. 

It is estimated that a litre of any gas contains 10 24 mole- 
cules. 

If a given volume of H, for example 1000 molecules, com- 
bine with an equal volume of CI, which, according to Ampere's 
Law, must contain the same number of molecules, there will 
be found two volumes of HC1, which will contain 2000 mole- 
cules. Since, however, each HC1 molecule contains an atom 
of H and an atom of CI, the 2000 acid molecules must contain 



INTR OD UCTION. \ J 

2000 atoms of each element ; but the 2000 atoms of H con- 
stitute the original amount of H or 1000 molecules. Hence 
the H molecule must contain two atoms. The CI molecule 
must also contain two atoms. 

The Laiv of Volumes. — In the combination of gases or 
vapors, the volume of the compound (as a gas) formed is 
sometimes equal to, but generally less than the sum of the 
volumes of its constituents. The law is that the volume of a 
gaseous compound bears a simple ratio to the volumes of its con- 
stituents. 

Thus one volume of H and one of CI combining form two 
volumes of HC1 ; two of H and one of O form two of steam ; 
three of H and one of N form hvo of ammonia. It is seen 
that in the first example there is no contraction of volume, in 
the second that three volumes are condensed into two, and in 
the third that four are condensed into hvo. 

Specific Volumes. — The product volume. It is learned from 
the examples just given that there are always two volumes of 
the gaseous compound. This doubled volume is called the 
normal or product volume of the gas. 

The Unit Volume. — The unit volume employed in discuss- 
ing the volumetric relation of gases and vapors is the volume 
of one atom of H. 

Chemical Terms. 

Hydrate. — The term hydrate is applied to a class of com- 
pounds which may be regarded as formed from H 2 by replac- 
ing half of its H by some metallic atom or radical acting as a 
metal. Thus, H-O-H (water), by exchanging an atom of H 
for one of K becomes KOH, potassium hydrate. 

Alkali. — The term alkali is applied to a class of very sol- 
uble bases, couiprising the hydrates of potassium, sodium, am- 
monium, etc. 

Amorphism. — The term amorphous is applied to substances 
without crystalline form. Thus charcoal, rock salt, and flint, 
are amorphous substances. 



18 CHEMICAL TERMS. 

Allotropism. — The term allotropic is applied to a condition 
of an element which can have different properties. Thus 
diamond and charcoal are allotropic forms of C. 

Isomerism. — The term isomeric is applied to substances 
having the same composition (so far as analysis can determine) 
but different properties. Thus, cane sugar and gum arabic, 
each of which contains C, H, and O, in the same proportions, 
are isomeric compounds. Isomerism is supposed to be due to 
a difference in the arrangements of atoms within the molecule. 

Catalysis, — The term catalysis is applied to a kind of action 
by which a substance seems to exert a chemical effect without 
itself changing. Thus, in preparing O from a mixture of 
potassium chlorate and manganese dioxide (Exp. 63) the latter 
substance does not change. 

Nascent State. — Substances just set free from combina- 
tion are said to be in a nascent state. They are then more 
active than after they have been some time free. Thus N 
and H, the constituents of ammonia, do not combine when 
mixed, but readily combine on being set free together from 
compounds. 

Water of Crystallization. — Water of crystallization is a 
definite amount of H,0 which certain substances take up on 
crystallizing, and to which they owe their crystalline forms. 
It may be driven off by heat. Thus the crystals of common 
alum contain 24 molecules of ELO. When the substance is 
heated, the crystalline form is destroyed and the residue is 
"burnt " alum. 

Mother Liquor. — The term mother liquor is applied to the 
liquid in which crystals have formed. It is a saturated solution 
(p. 20) of the substance which has crystallized. 

Effervescence. — Effervescence is the escape of a gas from 
a liquid in which it is either generated or has been held by 
pressure, as carbonic acid from dissolving marble or from 
soda water. 

Deliquescence. — Deliquescence is the solution of a sub- 
stance in H 2 which it absorbs from air. 



INTR OD UCTIOX. \ 9 

To Show Deliquescence. — Apparatus. — Piece of window glass. 
Material. — Small lump of potassium hydrate (KHO). 

Experiment 1. — Expose the KHO to air on the glass for half an hour. 
It will deliquesce. 

Efflorescence. — Efflorescence is the gradual crumbling of a 
crystal to powder on exposure to air. It is due to the escape 
of water of crystallization. 

To Show Efflorescence. — App. — Piece of window glass. Mat. — 10 
g. of Glaubers salt. 

Exp. 2. — Expose the salt to air in a warm place for several hours. It 
will become opaque and finally crumble. Weigh the powder. Its weight 
will be only about 5 g. 

Reaction. — A reaction is the action of chemical agents 
upon each other. A reagent is a substance by which reactions 
are produced. 

Alloy. — An alloy is a compound of two or more metals ; as 
brass, consisting of copper and zinc. An amalgam is an alloy 
in which one of the combining metals is mercury. 

Chemical Processes. 

Solution. 

Solution is the disappearance of a substance in a given 
liquid. The substance is said to be dissolved in the liquid, the 
liquid to be a solvent of the substance, and the combined mass 
of liquid and substance to be & solution of the substance. The 
dissolved substance loses its original physical properties. 

To Show Solution. — App. — 3 large test-tubes. Mat. — 1 g. each of 
sugar and starch, 0.3 g. zinc (Zn.), HC1, and H 2 0. 

Exp. 3. — Put the sugar and 5 c.c. of H 2 in a test-tube and shake 
the tube. The sugar dissolves in the H 2 0. Examine the solution by 
looking through it toward a good light. It should be as transparent as 
water. 

Exp. 4. — Put the Zn. and 2 c.c. of HC1 in a test-tube. The Zn. dis- 
solves in the HC1. 

Exp. 5. — Put the starch and 5 c.c. of H 2 in a test-tube, and shake 
the tube. The starch does not dissolve ; it mixes with the H 2 0. 

Weakening the cohesion among the molecules of a sub- 



20 CHEMICAL PROCESSES. 

stance, as by reducing it to powder, or by heating, hastens its 
solution. 

To Show that Pulverization and Heat Hasten Solution. — App. 
— 3 large test-tubes, mortar, and lamp. Mat. — 3 g. sugar iu 1 g. 
portions. 

Exp. 6. — Pulverize two of the portions of sugar. Put 10 c.c. of 
H 2 in each of the tubes and heat the H 2 in one of them to boiling. 
Then put, as nearly at the same time as possible, the portion not pow- 
dered in a tube containing cold H 2 0, and the other portions in the other 
tubes, and shake all the tubes at the same time. It will be seen how 
greatly solution may be hastened. 

A saturated solution is produced when a liquid has dissolved 
all of a substance that it can dissolve. 

To Make a Saturated Solution. — App. — Large test-tube and lamp. 
Mat. — Sugar and H 2 0. 

Exp. 7. — Dissolve by heating a little sugar in 2 c.c. of H 2 ; add a 
little more sugar and heat again until the solution is complete. Con- 
tinue adding sugar and heating until some of the substance remains 
undissolved. The liquid is a saturated solution. 

Crystallization. 

Crystallization is the arrangement of the molecules of a sub- 
stance in regular forms bounded by plane faces. Many sub- 
stances crystallize in passing from a liquid or a gaseous to a 
solid state. A hot saturated solution of a crystalline substance 
generally crystallizes on cooling slowly. 

To Show Crystallization. — App. — 4 test-tubes, 4 watch-glasses (or 
other shallow vessels), lamp, and piece of clean window-glass. Mat. — 
1 g. alum, 1 g. potassium dichromate, 2 g. saltpetre, 2 g. blue vitriol, 
0.2 g. ammonium chloride and H 2 0. 

Exp. 8. — Dissolve each of the first four substances in 5 c.c. of H 2 
and pour the solutions in the watch-glasses. The substances crystallize 
as the liquids cool. 

Exp. 9. — Dissolve the ammonium chloride in a small quantity of H 2 
and spread a drop of the solution on the glass. A beautiful crystalliza- 
tion will soon appear. 

If the crystals do not form, they may be produced by re- 
moving H 2 from the solution by evaporation. 

Crystals by Evaporation. — App. — Large test-tube, evaporating dish, 
and lamp. Mat. — 1 g. blue vitriol and H 2 0. 



INTRODUCTION. 21 

Exp. 10. — Dissolve by heating the vitriol in 10 c.c. of H 2 and allow 
the solution to cool. The crystals do not form. Reduce the solution 
by evaporation to one-third of its original bulk, and allow it to cool 
again. The crystals now form. 

Precipitation. 

Precipitation is the separation in a solid state, by chemical 
action, of a substance originally in solution. The solid is said 
to be precipitated and is called a precipitate. Precipitates are 
generally finely divided, but may also be gelatinous, curdy, 
crystalline, granular, or flocculent. 

To Show Precipitation. — App. — 2 test-tubes. Mat. — Solution of 
common salt (XaCl), solution of silver nitrate (AgX0 3 ) small iron tack, 
HCl,and solution of potassium ferro-cyanide. 

Exp. 11. — Put some of the XaCl solution in a test-tube and add to it 
a few drops of AgX0 3 . A white precipitate of silver chloride is formed. 
Preserve the contents of the tube. 

Exp. 12. — Dissolve by heating the tack in 2 c.c. of HC1, dilute the 
solution with H 2 to three times its bulk, and add a few drops of HX0 3 . 
Then add a little of the ferro-cyanide. A blue precipitate (Prussian 
blue) is formed. 

Filtration. 

Filtration, in chemistry, is the separation of a precipitate or 
other finely divided solid from a liquid with which it is mixed. 
The operation ordinarily consists in pouring the mixture on a 
properly folded piece of unsized paper placed in a funnel 
(p. 140), when the solid will remain on the paper and the liquid 
pass through. The liquid which has passed through is called 
the filtrate. 

To Show Filtration. — App. — Funnel containing a filter and sup- 
ported in a filter stand (p. 140). Mat. — The mixture from exp. 11. 

Exp. 13. — Pour the mixture on the filter. The solid and liquid will 
be completely separated. 

Distillation. 
Distillation is the vaporization of a liquid and the condensa- 
tion of the vapor. It affords a means of separating a liquid 
from the solid matter it may hold in solution, as H 2 from its 
foreign ingredients (Exp. 21), and also of separating two 



22 CHEMICAL PROCESSES. 

liquids which do not vaporize at the same temperature, as 
HoO and alcohol. 

Destructive or dry distillation is distillation in which the 
condensed products are formed by the decomposition of sub- 
stances (often in a dry state) heated in the retort. 

Heating on Charcoal. 
A small basin-shaped cavity is made in the coal by rotary 
motion with the spring end of a pair of pincettes or with a 
knife. The substance is put into the cavity and the flame in- 
clined downward upon it. 

Specific Gravity. (Sp. Gr.) 

The Specific Gravity of a body is its weight compared with 
the weight of an equal volume of another body taken as a 
standard. The standard for solids and liquids is distilled 
H 2 at a temperature of 39.2° F. (4° C.) ; the standard for 
aeriform bodies is air or H. 

The sp. gr. of a solid is found by weighing the body in air 
and in H 2 0, and dividing the weight in air by the difference 
of these weights, which is the weight of a volume of H 2 
equal to the volume of the solid. 

To Find Sp. Gr. — App. — Balance, small beaker (or other vessel) 
containing some H 2 0, small stool on which to support the beaker over 
the scale-pan, if the pan is not removed, and a fine thread. Mat. — 
Gold ring (or any small heavy body). 

Exp. 14. — AVeigh the body, then suspend it by means of the thread in 
the H 2 and weigh again. From these weights find the sp. gr. In 
making accurate determinations, the suspending thread should be coun- 
terpoised by a thread of equal weight. 

The sp. gr. of a liquid is found either by direct weighing, 
or by the depth to which an instrument, called the hydrometer ', 
will sink in it. 



INORGANIC CHEMISTRY. 



HYDROGEN (H). 1. 

The standard of atomic weights and of quantivalence ; a standard of spe- 
cific gravity. 

Properties. 
H is a transparent, colorless, odorless gas. It is the lightest 
and most diffusible substance known, being about 14J times 
lighter, and diffusing 4 times more rapidly than air. It burns 
with a slightly luminous and intensely hot flame, but does not 
support combustion. The product of the burning is H 2 0. 

Occurrence and Preparation. 

H occurs free in nature in meteors, in the gaseous products 
of volcanoes, and in the atmospheres of the sun and stars. In 
combination it is very abundant and widely diffused, being a 
constituent of H 2 and of all organic substances. 

H may be prepared from HC1 or H 2 S0 4 by means of zinc 
(Zn) or iron (Fe). 

To Prepare H from HC1. — App. — Generator, delivery tube, pneu- 
matic trough, and bottle gas-holder (p. 137). A generator is shown in 
Fig. 1. It consists of a wide-mouthed half-litre bottle with a closely 
fitting cork, through which 
is inserted a funnel tube 
reaching nearly to the bot- 
tom, and a short tube extend- 
ing just through the cork. 
The delivery tube may be a 
glass tube (d) with the ends 
bent in opposite directions, 
or a rubber tube with a short 
bent glass tube at one end. 
The glass delivery tube is 
connected with the generator 
tube by a piece of rubber 
tubing. Mat. — 20 g. sheet 




Fig. 1. — Gas Generator. 



(23) 



24 ILLUSTRATIONS OF THE PROPERTIES OF II. 

Zn cut into small pieces, or better, granulated Zn (prepared by pouring 
very hot melted Zn into cold H 2 0) and HC1. 

Exp. 15. — Arrange to collect the gas over H 2 (p. 136). Put the Zn 
in the generator and cover it with H 2 ; connect the delivery tube with 
the generator and let the free end dip into the H 2 in the trough. Then 
put some HC1 in the generator through the funnel tube. H is rapidly 
produced. Allow the bubbles that first pass off", which consist of air 
contained in the apparatus, to escape for a few seconds, then put the 
end of the delivery tube under the mouth of the bottle and collect the 
gas. Fill the bottle, adding more HC1 if necessary, and preserve the 
gas by leaving the bottle inverted in the trough. 

Reaction. — Zn + 2 HC1 = 2 H + ZnCl 2 (zinc chloride). 

Exp. 16. — Obtain ZnCl 2 , which is in solution in the tube, by pouring 
the contents of the tube on a filter and evaporating the filtrate. 

A large test-tube with a rubber cork containing a short glass tube, 
makes a convenient generator. If such generator be used, a smaller 
quantity of Zn should be used, more being added when necessary, and 
when the HC1 is exhausted the ZnCl 2 should be poured off before more 
acid is added. Instead of preparing gas enough for all the experiments 
at the same time, it may be prepared as needed and collected in the 
receiver to be used in performing the experiment. 

Illustrations of the Properties of H. 

Lightness of H. — App. — Common clay pipe, sheet of foolscap paper, 
2 ft. No. 16 wire, piece of strong thread, retort stand, pneumatic trough, 
and wide-mouthed 1. bottle with cover. The mouth of the bottle should 
be ground and provided with a ground glass cover which may be a piece 
of ground window-glass (p. 145). A piece of wet paper may be used 
as a cover. Mat. — The bottle of H from Exp. 15, and soap-bubble 
liquid prepared by stirring for several minutes shavings of castile soap 
with warm H 2 G, then pouring the mixture on a muslin filter, and add- 
ing to the filtrate about one-third of its volume of glycerine. 

Exp. 17. — Cork the gas bottle, place it erect on the table, and connect 
it with the H 2 bottle as for blowing (p. 136). Connect the clay pipe 
with the air-tube and start the H 2 0. Then, quickly grasping the air- 
tube between the thumb and a finger of one hand in order to regulate 
the flow of the gas, take the pipe in the other, and, using the soap- 
bubble liquid, inflate bubbles with H. The gas should not be allowed 
to pass until the liquid film is obtained on the pipe. The bubbles may 
be thrown off by a jerk of the pipe, or may be blown off. 

Exp. 18. — Make the foolscap paper into a cylinder, paste the edges 
carefully together, and close one end of it by pressing the halves of the 



HYDROGEN. 



25 



rim together and uniting them with paste. Then with threads attach 
the cylinder inverted to one end of the wire and suspend the wire 
from a ring of the stand, so that it will be horizontal. Fill the 1. 
bottle with H 2 and place it inverted on the shelf of the trough. Put 
the air-tube of the gas-holder into the bottle and transfer H as air is 
carried to a flame, filling the bottle. Cover the bottle, adjust it with 
its mouth directly under, and close 
to the mouth of the paper cylinder, 
and quickly remove the cover. The 
H rapidly expels air from the cylin- 
der, and the wire beam turns, show- 
ing the lightness of the gas. 

DlFFUSIBILITY OF H. App. 2 

soda-water bottles with the mouths 
ground (p. 145), so that one will 
stand inverted upon the other. 
Mat.—B.. 

Exp. 19. — Grease the ground sur- 
faces of the bottles, fill one of them 
with H and invert it upon the other 
(filled with air). Allow the bottles 
to stand thus connected for ten min- 
utes, then bring a lighted match to 
the mouth of each bottle. Explos- 
ions follow indicating that the gases 
have mixed (Exp. 73). Although air is 14J times as heavy as H, the 
latter passes down through the former. 

The H Flame. Singing Flame, Formation of H 2 by the Burning of 
H. — App. — Jet-tube consisting of a glass tube (p. 144) 8 or 10 in. long, 
with one end dravrn out until the opening is very small, piece of fine 
iron wire, and 2 or 3 glass tubes about | of an in. in diameter, and 1 to 
2 ft. long ; cylindrical lamp chimneys, or the necks of retorts, will 
answer the purpose. Mat. — H. 

Exp. 20. — Connect the jet-tube with the delivery tube of the gas- 
holder connected with the H 2 bottle, and force gas through it. After 
waiting a few seconds for the air to be expelled (see caution below) 
light the H jet. To test the temperature of the flame, hold in it the iron 
wire, which readily melts. Hold the jet-tube upright in one hand and 
lower around it one of the large tubes. The flame may produce a 
musical tone. If it does not, the tone may be produced by raising or 
lowering the tube, varying the size of the flame, using another tube, 
increasing the pressure by raising the H 2 bottle higher, or by redraw- 
2 




■Lightness of 11. 



26 COMPOSITION OF II 2 0. 

ing the point of the jet- tube. Try to make the flame sing. The sound 
is due to slight explosions quickly following one another, caused by air 
drawn up the tube. Notice the H 2 which has formed on the inner walls 
of the tube by the burning H. It is due to the H combining with of 
the air. 

Caution. — Great care should be taken in making experiments which 
require H to be lighted, to have the gas unmixed with air, as H and air 
form an explosive mixture. If the gas cannot be used immediately 
after it is prepared, it should always be kept until ready for use in an 
inverted bottle with its mouth under H 2 0. 

H Does Not Support Combustion. — App. — Wide-mouthed 1. bottle 
and pine splinter. Mat. — H. 

Exp. 21. — Fill the bottle with H. Light the splinter, and, holding 
the bottle inverted at a convenient height, push the lighted splinter into 
it and slowly withdraw it. The light, which kindles the gas at the 
mouth, is extinguished, but the splinter is relighted again when its 
glowing end reaches the burning H. Push the splinter into the gas 
again and withdraw it. 

Uses and Tests. 

H is burned (supported by a jet of O) to produce heat for 
melting platinum and other substances difficult to fuse, and 
to produce the calcium light. It is known mainly by its 
lightness, by its flame, and by its property of burning but not 
supporting combustion. 

Water (H,0). 

Properties and Occurrence. 
H 2 0, when pure, is a transparent, colorless, odorless, taste- 
less substance. It is a common solvent and the medium of 
many chemical changes. It is the most abundant of all sub- 
stances, covering three-fourths of the earth, forming, as vapor, 
part of the atmosphere, and constituting the chief ingredient 
of organic beings. It is called the life-blood of nature. 

Composition. 
H 2 is composed of 1 part by volume of O to 2 of H, or 
8 parts by weight of O to 1 of H. Its composition may be 
established both by analysis and synthesis. 



HYDROGEX. 27 

H,0 may be analyzed in various ways, the most satisfactory 
of which is by means of a powerful voltaic current (Nat. Ph., 
p. 285). Its composition is shown by synthesis in Exp. 20, 
the product of the combustion (due to the union of O and H) 
being H 2 ; also in Exp. 73, small drops of H 2 being pro- 
duced on the sides of the bottle in which the gaseous mixture 
is exploded. 

Impurities axd Purification. 

Natural waters are always impure. The impurities consist 

of various mineral and organic substances, either dissolved or 

held mechanically suspended, and sometimes of minute animals 

called infusoria. The purest natural water is rain or snow 



H 2 is freed from its suspended impurities by filtration. 
For household purposes it is generally purified by passing it 
through filters composed of alternate layers of charcoal, sand, 
and gravel. For important chemical operations it is sub- 
jected to a process called distillation (p. 21), and this process 
is sometimes repeated to render the water as nearly pure as 
possible. 

Distillation of JI 2 0. — App. — Distillling app., flask for receiver, retort 

stand, and lamp. The distilling app. may consist of a retort in which 

to heat the liquid and a glass tube to serve as a condenser. The tube 

should be about 18 

in. long and large 

enough to admit the 

end of the tube of 

the retort with a 

band of rubber or 

wet cloth around it. 

The ' condenser tube 

may be dispensed 

with and the tube 

of the retort put 

into the receiver, 

which should then 

, , , . TT ^ Fig. 3. — Distilling Apparatus. 

be supported in H.,0 

and covered with a wet cloth. Mat. — ELO. 




28 HYDROGEN DIOXIDE. 

Exp. 21. — Support the retort on a ring of the stand, placing it on 
wire gauze if an alcohol or gas lamp is to be used, and support the 
receiver with the free end of the condenser in it. Then put H 2 in the 
retort and heat, continuing the operation until nearly all the H 2 has 
passed over. 

Prove the purity of the distilled H 2 as follows: Evaporate slowly to 
dryness a few drops of it on a piece of clean glass. No residue will re- 
main. Evaporate a like quantity of H 2 from the retort in the same 
manner. A distinct spot of earthy matter will remain on the glass. 

Hydrogen Dioxide. (H 2 Q 2 ) 
H 2 2 is a colorless, oily liquid, which at 100° C. separates 
into O and H 2 with great energy. It is an active bleaching 
agent, possessing the property of bleaching without injuring 
the fabric. It is prepared by the action of HC1 or H 2 S0 4 on 
barium dioxide. 



PRACTICAL QUESTIONS. 

1. Name some compounds that contain H. Some that do not con- 
tain H. 

2. Of what classes of compounds is H a common element? What is 
the weight of a litre of H? A gallon? 

3. How much H can be prepared by using 10 g. of Zn ? By using 
lOg. ofHCl? 

4. How much Zn and HC1 would be required to produce 10 g. of H? 
To produce 1 gallon ? 

5. How can it be shown that H 2 is a product of the combustion 
of H? 

6. How much H must be burned to yield a gallon of H 2 ? 

I. How much H 2 will a pound of H yield in burning ? A gallon 
of H? 

8. The reaction in the preparation of H from H 2 S0 4 is expressed thus: 

Zn -f- H 2 S0 4 = 2 H + ZnS0 4 (zinc sulphate). 
By which of the two methods is the greatest weight of H produced with 
the same weight of acids ? 

9. Can you name any substances that do not contain H 2 ? 

10. How would you determine the amount of moisture in a substance? 

II. What weight of II in a gallon of H 2 ? What volume of H? 
What is the difference between spring H 2 and sea H 2 ? 



SODIUM GROUP. 



29 



12. "Why is rain H 2 "soft" and spring H 2 often "hard?" 

13. What process in nature is similar to the distillation of H 2 in the 
laboratory ? 

14. What weight of H 2 in 10 pounds of blue vitriol (67)? 

15. What is the difference in the percentage composition of H 2 and 
H 2 2 ? 

SODIUM GROUP. 

SODIUM, POTASSIUM, LITHIUM, RUBIDIUM, CvESIUM, SILVER. 

The elements of this group are monads. The compounds 
of each of them give peculiar colors to the flame of a lamp. 
Most of these compounds are soluble in H 2 0, and their oxides 
and hydrates, the caustic alkalies, are very corrosive. 



SODIUM (Na) 23o 

Properties. 
Na is a soft white metal with the lustre of silver. It 
quickly oxidizes in moist air, and hence is preserved in a 
liquid which contains no O, as naphtha or petroleum. Na de- 
composes H 2 at the lowest temperatures, liberating its H and 
combining with its O. 

Decomposing of H 2 BYNa. — Mat. — H 2 in a beaker (or wide-mouthed 
bottle) with cover, hot H 2 0, 2 pieces of Na as large as grains of wheat 
and red litmus paper. 

Exp. 22. — Put a piece of the Na on the H 2 0, and cover the vessel. 
The action is very energetic. The 
freed H passes into the air, and the 
new compound of and Na (sod- 
ium hydrate) dissolves in the H 2 0. 
Test the liquid with the litmus 
paper; it will color the paper blue. 
Evaporate it to dryness to obtain 
the hydrate. 

Exp. 23. — Put the other piece of 
Na on the hot H 2 0. The freed B 
burns, the flame being colored yel- 
low by vapor of the metal. 




Fig. 4. — Na on Hot Water. 



30 SODIUM CHLORIDE. 

Occurrence and Preparation. 
Na does not occur free in nature. Its chief source is com- 
mon salt, which is also the source of most of the Na com- 
pounds. It is commonly prepared by distilling a mixture of 
sodium carbonate and charcoal. 

Sodium Hydrate (J^aHO.) 

NaHO (caustic soda) is a white amorphous solid, with a 
strong affinity for H 2 0, in which it readily dissolves, a very 
caustic and alkaline solution being formed. In air it deli- 
quesces and absorbs C0 2 , changing to a carbonate. It com- 
bines with fats and oils to form hard soaps. NaHO is pre- 
pared by mixing milk of lime (whitewash) with a solution of 
sodium carbonate, JSaHO and calcium carbonate being 
formed. " Concentrated lye " is an impure NaHO. 

Sodium Chloride (l¥aCl.) 
Properties. 
NaCl (common salt) is a white crystalline salt, crystallizing 
in cubes. Its slightly bitter taste is due to the presence of a 
little magnesium chloride. It dissolves in about three times 
its weight of HX), and is nearly as soluble in cold as in hot 
H 2 0. 

To Prepare Crystals of NaOl. — App. — 2 small beakers and app. for 
filtering. Mat.— NaCl and H 2 0. 

Exp. 24. — Make a strong solution of NaCl in one beaker, filter it into 
the other, and place the filtrate where it will be undisturbed for several 
hours. Little cubes of the substance separate ; examine them with a lens. 



Occurrence and Preparation. 
NaCl occurs in solution in the ocean and in saline springs, 
and in a mineral form as rock salt. The water of the ocean 
contains about 4 oz. of NaCl to the gallon. Rock salt is 



SODIUM GROUP. 31 

abundant. Near Cracow, Poland, there is a vein 500 miles 
long, 20 miles wide, and 1200 feet thick. It is also extensively 
mined at Stassfurt in Prussia, Salzburg in Austria, Petit Anse 
in Louisiana, and various other places. 

NaCl is generally obtained by evaporation from its solution, 
which, in climates sufficiently warm, is effected by the heat of 
the sun. When natural deposits of salt are mixed with large 
quantities of earthy impurities, the salt is obtained by letting 
H 2 into the bed, allowing it to remain until saturated, and 
then evaporating the solution. When the saturated solution 
is evaporated rapidly, the product is fine salt ; evaporated slowly, 
it is coarse salt. The most extensive salt works in the United 
States are in Onondaga County, New York. 

Uses. 
NaCl is an essential constituent of our food.* It is used in 
large quantities for preserving meat and fish, in glazing earth- 
enware, and in preparing other Na compounds. It is used in 
the laboratory in the preparation of CI and HC1. 

Sodium Sulphate (JYa 2 S0 4 ). 

Na 2 S0 4 is a white salt easily soluble in H 2 0. Its solution 
produces crystals called Glauber's salt (IS"a 2 S0 4 +10 H 2 0), 
which effloresce in dry air, forming Na 2 S0 4 . It is an inter- 
mediate product in the preparation of sodium carbonate from 
NaCl. 

Sodium Carbonate (Jtfa 2 C0 3 ). 

Na 2 C0 3 is a white alkaline salt, soluble in H 2 0. Its solu- 
tion produces crystals, called sal soda (Na 2 C0 3 +10 H 2 0, 
washing soda), which effloresce in dry air, forming Na 2 C0 3 . 

* Common salt is universally prized as an article of food. It is said 
that in some parts of Africa the most valuable possessions, even wives 
and children, are bartered for salt, and that its use is a sign of riches. 
Depriving criminals of the use of salt was a mode of punishment in 
ancient times. It is estimated that each person in the United States 
consumes annually from 50 to 60 lbs. of salt. 



32 SODIUM NITRATE, SODIUM B I BORATE. 

Na 2 C0 3 is prepared from NaCl by Leblanc's process,* which 
may be briefly stated as follows : 

First Stage. — A mixture of NaCl and H 2 S0 4 is heated, 
Na.,S0 4 and HC1 fumes being produced. The latter are con- 
ducted over wet coke to form common HC1. 

Second Stage. — The N a 2 S0 4 is then heated in a reverberatory 




Fig. 6. — Reverberatory Furnace. 

furnace with chalk or limestone and fine coal. " Black ash," 
consisting mainly of Na 2 C0 3 and CaS, is produced. The 
"black ash" is washed with warm H 2 0, the solution evapo- 
rated to dryness, and the residue roasted with sawdust. The 
product thus obtained, containing about 80 per cent, of 
NajCO,, is the "soda ash" of commerce. 

Hydrogen Sodium Carbonate (HNaC0 3 , bi-carbonate of soda) 
is a white powder prepared by exposing Na 2 C0 3 to.C0 2 . It 
is used in raising bread, etc., and in effervescing powders, and 
is known by cooks and grocers as "soda." 

JSTa Nitrate (JBfaNOi), J^ci Biborate (Wa 2 B 2 0,). 

NaNO, (soda-saltpetre) is a white crystalline salt, found 
in the desert districts of Peru and Nevada. It is used in pre- 
paring HX0 3 and as a fertilizer. 

"K&fifii (borax) is a white crystalline salt soluble in H 2 0. 
It occurs in many mineral springs, in certain lakes, as Borax 

* Sodium carbonate was formerly produced only from the ashes of sea 
weeds growing along the coasts of France, Spain, and Scotland, and it 
became so high in price during the French Revolution that Napoleon 
offered a premium for the discovery of a process by which it could be 
more cheaply produced. To this circumstance we are indebted for Le- 
blanc's process, which came into use about the year 1820. This dis- 
covery, by cheapening the production of many much-used products, is 
justly regarded as a very important event in the history of chemistry. 



SODIUM GROUP. 



33 




Lake of California, and in ancient lake beds, as the " marshes " 
of Nevada. It is manufactured in large quantities from the 
crude boric acid of Tuscany, and from calcium borate of 
Nevada. 

POTASSIUM (K) 39.1. 
Properties. 

K closely resembles Na in appearance and properties ; it 
has, however, a bluish color, 
and decomposes ILO with so 
much energy that the heat 
produced is sufficient to kin- 
dle the H. 

Decomposing op H 2 by K. — Mat. 
— H 2 in a beaker (or wide- 
mouthed bottle) with cover and 
piece of K as large as a grain of 
wheat. 

Exp. 25.— Put the K on the H 2 
and cover the vessel. The H burns 
with a purplish-red flame, the color being due to a small quantity of 
the vaporized metal. 

Occurrence and Preparation. 
K does not occur free in nature, but its compounds are 
widely distributed, being found in all fertile soils. It is pre- 
pared by heating intensely a mixture of potassium carbonate 
and charcoal. 

K. Hydrate and Other K. Compounds. 

Potassium Hydrate (KHO, caustic potash) closely resembles 
NaHO, but it is more strongly alkaline. Its preparation is 
similar to that of NaHO. It combines with fats and oils to 
form soft soaps. 

Potassium Cliloride (KG) closely resembles NaCl. It is found 
in sea water and in the saline deposits at Stassfurt. 

Potassium Bromide (KBr) and Iodide (KI) resemble the chlo- 
ride. They are used in medicine and photography. 



Fig. 7. — K on Water. 



34 POTASSIUM CHLORATE. 

Potassium Cyauide (KCX) is a white, fusible, poisonous solid 
used in electro-plating. It poisons when in contact with a cut 
or scratch in the skin. 

Potassium Carbonate (K 2 C0 3 ). 

K 2 C0 3 is a white crystalline salt, deliquescent and soluble 
in H 2 0. It is prepared from the sulphate by Leblanc's pro- 
cess, and also from the ashes of plants. The refined product 
is called pearlash. K 2 C0 3 is used in the manufacture of soap 
and glass, and in preparing other K compounds. 

To Obtain K 2 C0 3 from Wood Ashes. — App. — App. for filtering and 
an evaporator. Mat. — Wood ashes and hot H 2 0. 

Exp. 26. — Fill the filter with ashes and pour hot H 2 on them, col- 
lecting the liquid in the evaporator. Pass tfie liquid through the ashes 
several times and evaporate it to dryness. The residue is crude K 2 C0 3 . 

Hydrogen Potassium Carbonate (HKC0 3 , bicarbonate of 
potash, saleratus) is a white crystalline substance prepared by 
passing CO, through a solution of JLCO3. 

Potassium Xitrate (KXG 3 ). 

KNOj (nitre, saltpetre) is a white crystalline salt, very sol- 
uble in hot £LO, and an energetic oxidizing agent. It is a 
natural product, its chief source being the soil of certain dis- 
tricts of India, Persia, and other tropical regions. It is used 
chiefly as an ingredient of gunpowder, which is a mixture of 
6 parts KXO;, 1 part 6 and 1 part charcoal. 

KXO3 as an Oxidizing Agent. — App. — Piece of porcelain (or earth- 
enware), lamp, and iron wire 6 in. long. Mai. — 2 or 3 g. KX0 3 and £ g. 
finely powdered charcoal. 

Eoqp. 2 7. — Mix the KX0 3 and C together, put the mixture on the por- 
celain, and ignite it with the wire heated. The salt decomposes with 
vivid combustion, its uniting with C to form C0 2 . 

Potassium Chlorate (KC10 3 ). 

KCIO3 is a white crystalline salt, soluble in H 2 0, and an 
energetic oxidizing agent. It is prepared by the action of CI 
on milk of lime, followed by the conversion of the calcium 



SODIUM GROUP. 35 

chlorate thus formed into KC10 3 by means of potassium chlo- 
ride. It is much used in calico printing, medicine, pyro- 
techny, and in making some kinds of friction matches. 

KCIO3 as ax Oxidizing Agent. — App. — Mortar, anvil (or flat-iron), 
hammer, piece of tin 4 or 5 in. square, and half a sheet of foolscap 
paper. Mat. — Piece of phosphorus (P) as large as a pin's head, 1\ g. 
KCIO3, 2 g. white sugar, and strong H 2 S0 4 . 

Exp. 28. — Powder the KC10 3 finely (see caution below), put the P on 
a piece of paper, cover it with KC10 3 and wrap the two substances 
tightly in the paper j then place the package on the anvil and strike it 
with the hammer. The stroke is followed by a sharp explosion. 

Caution. — In pulverizing KC10 3 , the mortar and pestle should be clean, 
and the crystals should not be struck nor strong pressure used. 

Exp. 29. — Powder the sugar and mix it thoroughly with the remain- 
ing KCIO3 ; pour the mixture in a paper tube ; then put the tube on the 
tin, and let fall on the mixture, at one end of the tube, a drop of H 2 S0 4 . 
The mass burns with great energy. 

Tests for Na and K. 

The flame tests are simplest. Na salts color the upper part 
of an alcohol or gas flame yellow, and K salts, purple or 
violet. Flame tests are made by placing a drop of the solu- 
tion of the substance by means of a platinum wire in the 
flame ; one end of the wire (which should be about as thick 
as coarse sewing thread) is bent into a small loop, and this is 
dipped into the solution, and then put into the flame, (p. 146). 

Exp. 30. — Make flame tests for Na and K, using solutions of NaCl 
and KNOg. Insert the wire at the point of the blue cone. 

Exp. 31. — Prepare Na 2 S0 4 and K 2 S0 4 by adding (not in excess) dilute 
H 2 S0 4 to solutions of Na 2 C0 3 and E^COg. Obtain crystals of the sub- 
stances. Exp. 32. — Prepare crystals from strong H 2 solutions of 
Na 2 C0 3 and KgCOg. Expose for several hours a crystal of each sub- 
stance to dry air, and one of each to moist air, and notice how the 
crystals are changed by this treatment. 

The other members of the Na group are rare metals. 
Lithium is the lightest metal known, having a sp. gr. of only 
0.59. Its volatile compounds color the flame carmine red. 
These metals are always found with Na and K, but in very 
small quantities. 



36 SILVER CHLORIDE; NITRATE. 

SILVER (Ag) 108. 

Properties. 
Ag is a white, very malleable, ductile metal, and the best 
conductor of heat and electricity. Sp. gr. 10.5. It does not 
change in air, but blackens in air containing hydrogen sul- 
phide, which is always present in rooms heated with coal fires. 
The black coating is silver sulphide. Ag dissolves readily in 
HNO,. 

Occurrence and Preparation. 

Ag is widely distributed and somewhat abundant in nature. 
It frequently occurs in the metallic state, but generally in 
combination, its most abundant ore being the sulphide mixed 
with lead sulphide. A large deposit of the carbonate occurs 
at Leadville, Colorado. 

Among the richest of the long-known silver mines are those 
of Mexico and Peru. The famous Comstock lode, in Nevada, 
has proved the richest mine in the world, having yielded 
870,000,000 worth of Ag in seven years. 

Ag is separated from its ores in several ways. By the 
amalgamation process a silver amalgam is produced by the ad- 
dition of mercury to the ore, and the mercury is removed from 
the compound by distillation. By the cupel process an alloy 
of Ag and lead is formed, and the lead removed by oxidation. 

The various uses of Ag are well known. It is generally 
alloyed with a small amount of copper to increase its hard- 
ness. Our silver coins contain 10 per cent, of copper.* 

Ag Chloride (AgCl), Ag Nitrate (AgJYOJ. 

AgCl is a white crystalline salt which may be prepared by 
adding HC1 or a solution of NaCl to a solution of AgN0 3 . 
It is frequently found as a compact mineral which, from its 
horny texture, is called horn silver. 

*The date of the first use of silver is unknown. According to the 
Old Testament it formed part of the riches of Abraham, and was abund- 
ant in Solomon's reign. Pliny (born A. D. 23) speaks of a mine which 
supplied him 300 lbs. of the metal a day. Silver was called by the 
alchemists Luna or Liana. Silver was first known as " white gold." 



SODIUM GROUP. 37 

AgN0 3 is a white crystalline salt, soluble in H 2 ; when 
melted and cast into sticks it is called lunar caustic. When 
in contact with organic matter, AgN0 3 is decomposed by light, 
the reaction producing a black stain which cannot be removed 
by washing. Hence its use in the preparation of hair dyes 
and indelible ink. It is used in surgery and photography. 
It is prepared from a solution of Ag in dilute HN0 3 . The 
nitrate stains and indelible ink can be removed by applying 
a solution of potassium cyanide, (p. 34). 

Exp. 33. — Prepare AgCl from a solution of a piece of Ag coin in 
HN0 3 . It is formed as a white cheesy precipitate. The copper remains 
in solution. Expose the AgCl to sunlight and it will become brown. 

Tests. 

Most Ag compounds yield Ag when heated in a blowpipe 
flame, and Ag compounds in solution give, with any soluble 
chloride, precipitates of AgCl which darken in sunlight 
(Exp. 33). 

Exp. 34. — Obtain a globule of Ag by heating some AgCl with some 
dry potassium carbonate (K 2 C0 3 ) on charcoal. The CI is removed by 
the K of the K 9 CO„. 



PRACTICAL QUESTIONS. 

1. What weight of Na in 5 oz. of NaCl ? Of K in 5 oz. KN0 3 ? 

2. "What is the composition of lye obtained from wood ashes? 

3. What Na compound contains the largest amount of Na ? What 
K compound the largest amount of K? 

4. If intrinsic values only are considered, what relation should the 
value of Na 2 C0 3 bear to Na 2 C0 3 + 10 H 2 ? 

5. Why is HNaC0 3 used in making bread, cakes, etc.? 

6. For hurried baking which is better, "soda" or "saleratus?" 

7. How many litres of C0 2 can be obtained from 10 g. of Na 2 C0 3 ? 
10 g. of HNaC0 3 ? 10 g, of Na 2 C0 3 + 10 H 2 ? 

8. What Ag compound contains the largest amount of Ag ? 

9. How much AgCl could be made from a half dollar? (Find the 
weight of the coin.) 

10. How much NaCl would be required to precipitate 1 g. of Ag? 
How much HC1 ? 



38 



CHLORINE. 



CHLORINE GROUP. 

CHLORINE, BROMINE, IODINE, *FLUORINE. 

The elements of this group are monads. They all form 
acids with H, and salts, of which common salt is the type, 
with certain metals. Their chemical energies are inversely as 
their atomic weights. 

CHLORINE (CI) 35.5. 

Properties. 

CI is a yellowish-green suffocating gas, nearly 2j times as 

heavy as air, and very soluble in H 2 0. It combines with 

certain substances, as H, oil of turpentine, and antimony, with 

great energy, and is an active bleaching agent. 

< 'nation. — Experiments with CI should be made in a draught of air. 
The strong gas should not be inhaled. 

Occurrence and Preparation. 
CI does not occur free in nature, but is abundant in combi- 
nation. It occurs most abundantly in common salt (NaCl) 
forming about three-fifths by weight of this compound. 

CI may be prepared from HC1 by means of manganese 
dioxide (Mn0 2 ) ; from NaCl 
by means of Mn0 2 and 
H 2 S0 4 ; or from bleaching 
powder (CaOCL) by means 
of H 2 S0 4 . 

To Prepare CI from HC1. — 
App. — Half 1. flask with cork to 
which a delivery tube is attached, 
retort stand, 3 wide-mouthed half 
1. bottles with covers, and lamp. 
The tops of the bottles should be 
greased to enable the covers to fit 
more closely. Mat. — 5 g. Mn0 2 , 
and HC1. 




Fig. 



-Preparation of CI. 



Exp. 35. — Support the flask on a rii g of the stand, place the bottle 



CHLORINE GROUP. 39 

erect on the table and put the free end of the delivery tube into it, ex- 
tending it to the bottom. Put the Mn0 2 in the flask and add to it about 
10 c.c. of HC1, then cork the flask and heat gently. As the CI collects, 
the air in the bottle is slowly expelled. When the bottle is full, which 
is indicated by the yellowish-green color of the entire contents, carefully 
cover it. Fill also the other bottles and preserve the CI. 

CI is not collected over H 2 because it is so readily absorbed by H.,0. 
It may be collected over hot H 2 or brine. 

Reaction.— Mn0 2 + 4 HC1 = 2 CI + 2 H 2 + MnCl 2 (man- 
ganese chloride). 

Exp. 36. — Obtain the MnCl 2 by pouring the contents of the generator 
on a filter and evaporating the filtrate. 

To Prepare CI from XaCl and from CaOCl 2 . — App.— 2 test-tubes and 
lamp. Mat.— 2 g. XaCl. 2 g. Mn0 2 , 2 g. CaOCl 2 , H 2 and H 2 S0 4 . 

Exp. 37. — Put the XaCl and Mn0 2 in one tube and the CaOCl 2 in the 
other. * Put in each tube some H 2 and 2 or 3 c.c. of H 2 S0 4 , and heat. 
CI, known by its color and smell, is given off from each tube. 

Illustrations of Properties. 

Combining of CI and H. — The App. and Mat. used to generate CI, 
and H, soda-water bottle, small pneumatic trough containing brine and 
narrow strip of blue litmus paper. 

Exp. 38. — Half fill the soda-water bottle, screened from strong light 
by a wrapping of cloth or paper, with CI, 
and the remainder with H. Then remove 
the bottle from the trough and quickly 
bring a lighted match to its mouth. The 
gases combine with a sharp explosion, form- 
ing HC1. Prove the presence of HC1 by 
wetting the litmus paper and suspending it 
in the bottle just after the explosion has 
occurred. 

Dissolving of CI in H 2 0. — App. — The 
generator used in Exp. 15 and a qr. 1. bot- 
tle. Mat.— Bottle of CI, 2 g. Mn0 2 , HC1, Fig. 9.— Combining of H 
a id H 2 0. and CI. 

Exp. 39. — Put some H 2 in the bottle of CI, close the bottle with the 
hand, and shake it. The H 2 absorbs the gas, the vacuum produced 
causing the hand to be pressed tightly against the mouth of the 
bottle. 

Exp. 40. — Put some H 2 in the qr. 1. bottle and pass a current of CI, 
prepared as in Exp. 35, through it by extending the delivery tube to the 




40 



CHLORINE. 




Fig. 10. — Preparing 
Chlorine Water. 




bottom of the bottle. The H 2 absorbs the gas, forming chlorine water. 
When the H 2 has become saturated (smells 
strongly of CI), preserve it by carefully cork- 
ing the bottle. 

Burning op Oil of Turpentine (C 10 H 16 ) in 
CI. — App. — Test-tube, lamp, and strip of fil- 
ter paper about an in. wide. Mat. — Bottle of 
CI and C 10 H 16 . 

Exp. 41. — Put 5 or 6 c.c. of C 10 H 16 in the 
tube and heat, then dip the 
paper, folded two or three 
times lengthwise, into it and 
thrust the paper into the CI. 
A dense smoke is produced 
and the paper may ignite. 
The CI combines with the H 
of the oil, liberating the C (smoke). 

Burning op Antimony (Sb) in CI. — App. — Lamp, 
mortar, and piece of tin. Mat. — Bottle of CI and 1 g. Sb. 
Exp. 42. — Powder finely the Sb, dry it on the tin 
over the lamp, and sprinkle it into the CI. The metal FiG^ll. — C, ft H. 
ignites and falls glowing to the bottom of the bottle, 
a portion of the product formed appearing as a heavy 
white smoke. 

CI as a Bleaching Agent. — App. — 3 small beakers, 
retort stand, and kerosene lamp. Mat. — 5 g. Mn0 2 , 5 
water, IIC1, H 2 S0 4 , chocolate-colored calico, ink-stained muslin, piece 
of paper on which there is printing and writing with ink and with a lead 
pencil, and small quantities of solutions of litmus, of indigo, and of an 
aniline color. 

Exp. 43. — Put some Mn0 2 and HC1 in each beaker. Cover one of 
the beakers with a piece of the calico, another with a piece of the 
stained muslin, and the third with the paper ; wet the covers with H 2 0, 
and support the beakers in turn for several minutes over the lamp with a 
low name. The calico will be bleached and the spots and ink writing 
removed; the printing and pencil writing, however, will remain. 

Exp. 44. — Nearly fill the test-tubes with CI water and put in each a 
few drops of one of the colored solutions. The colors disappear. Pour 
some CI water on ink writing and notice the effect. 

Exp. 45. — Put the CaOCl 2 and H 2 in a beaker, and some dilute H 2 S0 4 
in another beaker. Immerse a piece of the calico in one liquid, then in 
the other several times ; wash the calico. Its color is destroyed. 



Burning 
CI. 



3 test-tubes, 
. CaOCL, CI 



CHLORINE GROUP. 41 

In bleaching on a large scale, the article is first cleansed of grease by 
boiling it in an alkali, it is then saturated with dilute H 2 SO^, and 
finally passed through a solution of CaOCl 2 . The H 2 S0 4 liberates CI 
from the powder. 

The action of CI in bleaching is to take H from H 2 0, the 
O of which combines with the color, forming a colorless com- 
pound. Hence CI must contain H 2 in order to bleach. 

To Show that Dry CI Will Not Bleach. — App. — Test-tube and roll 
of paper made out of a strip of paper ^ in. wide that will fit closely 
in the tube. Mai. — 2 g. Mn0 2 , HC1, calcium chloride (CaCl 2 ) or bleach- 
ing powder, and H 2 0. 

Exp. 46. — Put the MnO, and some HC1 in the test-tube, push in the 
roll of paper 2 in. and cover it with a layer of CaCl 2 1 in. thick. Then 
cover the tube with a piece of dry calico and heat gently. The CI is 
dried by the CaCl 2 and has no action on the calico. Put a few drops 
of H 2 on the calico, and it will bleach as previously shown. 

Uses and Tests. 

The chief use of CI is for bleaching. It is also used as a 
disinfectant, and for this purpose is conveniently produced by 
exposing bleaching powder mixed with H 2 to air, the C0 2 of 
the air decomposing the substance. 

CI is known by its odor and color. It may be detected in 
many compounds by adding to a solution of the compound a 
solution of silver nitrate. A white precipitate of silver chlo- 
ride, which is insoluble in HX0 3 , is produced. 

Exp. 47. — Prove the presence of CI in common salt. 

Hydrochloric Acid (If CI J. 

HC1 (hydrogen chloride, muriatic acid), the only known 
compound of H and CI, is a colorless, pungent acid gas. It is 
very soluble in H 2 0, one volume of H 2 0, at 0°C. dissolving 
more than 500 volumes of the gas. The solution of HC1 
in H 2 is common muriatic acid. HC1 dissolves most of the 
metals and their oxides. Compounds formed by the action 
of HC1 on metals, etc., are called chlorides. 

HO occurs free in nature in the gaseous products of active 
volcanoes, and in the waters of some volcanic districts. It 



42 HYDROCHLORIC ACID. 

may be prepared from H. 2 S0 4 and common salt (NaCl). 
Most of the H(^l of commerce is a secondary product of the 
alkali manufacture. 

To Prepare HC1. — App. — Same as tiiat used in preparing CI ; only 
one qr. 1. bottle is needed. Mat. — 5 g. NaCl, 5 c.c. H 2 S0 4 and bit of 
blue litmus paper. 

Exp. 48. — Arrange to collect the gas as CI was collected. Stick with 
11,0 the litmus paper on the rim of the bottle, put the NaCl and H 2 S0 4 
in the flask, and heat. Fill the bottle ; it is full when the litmus paper 
turns red. Cover the bottle and preserve the gas. 

Reaction.— NaCl -f H 2 S0 4 = HC1 + HNaS0 4 (hydrogen 
sodium sulphate). 

Exp. 49. — Obtain the IINaS0 4 by pouring the contents of the flask on 
a filter and evaporating the filtrate. 

Dissolving of HC1 in H 2 0. — App. and Mat. — The bottle of HC1 gas 
from Exj). 48, a shallow dish containing H 2 colored slightly blue with 
litmus, the app. and half the NaCl and H 2 S0 4 used in Exp. 48 and qr. 1. 
bottle nearly full of H,0. 

Exp. 50. — Invert the bottle of gas in the blued H 2 0. The H 2 rises 
in the vessel and turns red by the action of the acid. 

Exp. 51. — Pass a current of HC1 gas. prepared as in Exp. 48, through 
the H 2 in the bottle as shown in Fig. 10. The solution of the gas in 
the H.,0 thus made is ordinary HC1. In preparing the acid in large 
quantities, iron cylinders are used as generators, and the gas is collected 
in a series of earthenware bottles. 

HC1 as a Solvent. — App. — 4 small test-tubes and lamp. Mat. — HC1 
and about I g. each of zinc, iron, iron rust, and black oxide of copper. 

Exp. 52. — Put the metals and oxides in the tubes, add about 1 c.c. of 
HC1 to each, and heat. They readily dissolve, their chlorides being 
formed. The chlorides may be obtained by evaporation. 

Uses and Tests. 

HC1 is much used in the chemical laboratory. It is used 
also in preparing bleaching powder and gelatine, as a solvent 
of metals, and for various other purposes. 

HC1 produces with ammonia dense white fumes (NH 4 )C1 
(Exp. 122), and with a solution of silver nitrate (AgN0 3 ) a 
milky precipitate which is insoluble in (NH 4 )HO, but solu- 
ble in HX0 3 . 



CHLORINE GROUP. 43 

Exp. 53. — Make these tests, using for the latter very dilute acid and 
only a few drops of the AgX0 3 solution. 

Aqua Hegia. 

Aqna Regia is a mixture of 3 volumes of strong HN0 3 with 
5 volumes of strong HC1. It is used for dissolving gold and 
other metals not soluble in separate acids. 

Aqua Regia as a Solvent. — App. — 2 small test-tubes. Mat. — 2 small 
pieces of gold leaf, HN0 3 and HC1. 

Exp. 54. — Put 1 or 2 c.c. of HN0 3 in one tube and 2 or 3 c.c. of HC1. 
in the other, and put a piece of gold leaf in each tube (the leaf may be 
transferred to the tubes on the moistened end of a glass rod or lead 
pencil). Neither acid dissolves it. Mix the contents of the tubes in 
either tube and the gold rapidly dissolves, forming gold chloride. 

In this action the acids decompose each other, liberating CI, 
which acts (in the nascent state) on the gold. 

FLUORINE (F) 19. 

F is a gas, but it cannot be readily obtaiDed in a free state ; 
for when it is freed from a compound it immediately forms 
another with any substance with which it comes in contact. 
It is the only element that does not combine with O. It forms 
with H hydrofluoric acid (HF) which has a strong affinity for 
silicon, and may therefore be used for etching glass. 

F occurs in the minerals, fluor spar (calcium fluoride, CaF 2 ), 
found in many localities, and cryolite (sodium and aluminum 
fluoride), found in extensive beds in Greenland. 

To Etch with HF. — App. — Leaden dish, retort stand, and lamp. The 
dish may be made by sawing a ring f of an in. wide from a piece of 
lead pipe, and soldering a piece of sheet lead to one of its ends for a 
bottom. Vessels of other material may be used, but they may be 
attacked either by the HF or the H 2 S0 4 . Mat. — 2 g. CaF 2 , and H 2 S0 4 , 
square of glass large enough to cover the cup, and lump of beeswax. 

Exp. 55. — Coat the glass with the wax by heating the wax and daub- 
ing it on the glass, then heating the glass and allowing it to cool. If 
the coat is uneven, heat again. Now write on the glass through the 
wax with a pin or other pointed instrument. 

Powder the CaF 2 , put it into the dish and make it into a thin paste 
with H 2 S0 4 ; then cover the dish with the coated glass, waxed surface 




44 IODINE. 

down, and support it over a very low flame. The wax must not melt : 
this may be prevented by covering the glass 
with a wet cloth. In half an hour remove the 
coating, scraping off most of it, then rubbing 
the plate with a cloth saturated with alcohol, 
and the writing will be etched on the glass. 

Fig. Ifrw— Etching with Etchings may be conveniently made on the 
convex surfaces of a Avatch glass or bulged 

lamp chimney, since H 2 may be put in the concavity, to prevent the 

wax from melting. 

BROMINE (Br) 80. 

Br is a brownish-red, volatile liquid, with a suffocating and 
offensive odor. It acts chemically much like CI, but has less 
energy. Br does not occur free in nature, and its principal 
compound is magnesium bromide, found in sea Avater and in 
the waters of many saline springs. It is prepared very ex- 
tensively from mother liquors obtained from Stassfurt in work- 
ing the salts of potassium and magnesium. Some of the 
bromides are used extensively in photography and medicine. 

To Prepare Br from Potassium Bromide (KBr). — App. — 3 test-tubes 
and lamp. Mat.—\ g. KBr, and H 2 0, Mn0 2 , HC1, CI water (Exp. 40), 
and ether. 

Exp. 56. — Dissolve the KBr in 5 c.c. of H. 2 0. Put a little Mn0 2 in a 
clean dry test-tube, add to it a few drops of HC1, then some of the KBr 
solution, and heat gently. The dark red vapor of Br will soon appear. 
The Br is expelled from the KBr by the CI. 

Exp. 57. — To the remainder of the KBr solution, add some CI water, 
then some ether, and shake the mixture. A reddish layer of Br dissolved 
in ether will form at the top of the liquid. 

IODINE (I) 127. 

Properties. 
I is a blue-black, crystalline solid with a metallic lustre. 
When gently heated, it yields a beautiful purple vapor, nearly 
9 times as heavy as air, which crystallizes on cooling. It is 
only slightly soluble in H 2 0, but dissolves readily in alcohol 
and ether. It acts chemically somewhat like CI and Br, with 
less energy than Br. 



OXYGEN GROUP. 45 

Vapor of I. — App. — Long dry test-tube and lamp. Mat. — A few 
crystals of I. 

Exp. 58. — Put the I in the tube and heat, holding the tube so that the 
vapor can be seen to best advantage. The I will crystallize on a cold 
part of the tube. Heat again and reconvert it into vapor. 

Dissolving of I in Alcohol. — App. — Test-tube. Mat. — A few crys- 
tals of I and alcohol. 

Exp. 59. — Shake the I in the test-tube with some alcohol. It dis- 
solves, tincture of I being formed. 

Occurrence and Preparation. 

I does not occur free in nature. It is found in small quan- 
tities, combined with potassium and sodium, in sea water and 
in the waters of many saline and mineral springs. 

To Prepare I from Potassium Iodide (KI). — App. — 2 test-tubes and 
lamp. Mat. — 0.3 g. KI and H 2 0, Mn0 2 and HC1. 

Exp. 60. — Dissolve the KI in 1 c.c. of H 2 0. Put a little Mn0 2 in a 
clean dry test-tube, add to it a few drops of HC1, then some of the KI 
solution and heat gently. The violet vapor of I will soon appear. 

Uses and Tests. 

I compounds are used in photography, in the chemical 
laboratory, and in medicine. I is known by its vapor. A 
delicate test is the blue color it forms with starch. 

Starch Test for I. — App. — Small test-tube, lamp, and large, wide- 
mouthed bottle. Mat. — Tincture of I, a few crystals of I, starch paste 
(the kind used for laundry purposes), and strip of filter paper. 

Exp. 61. — Mix a little starch paste with some H 9 in the test-tube, 
and add a few drops of tincture of I. The liquid becomes deep bine. 
Heat the liquid, and its color disappears ; the color will reappear again 
when the liquid cools. 

Exp. 62. — Put the I in the bottle ; coat the strip of paper with starch 
paste and suspend it in the bottle. The paper is slowly colored blue by 
I vapor. 

OXYGEN GEOTJP. 

OXYGEN, SULPHUR, SELENIUM, TELLURIUM. 

The elements of this group are dyads. They are especially 
characterized by their wide range of affinities. 



46 OXYGEN. 

OXYGEN (O) 16. 

Properties. 
O is a transparent, colorless, odorless gas about 1.1 times as 
heavy as air. It has great chemical activity, and combines 
with all the elements except fluorine, the combination produc- 
ing oxides. 

Occurrence and Preparation. 
O occurs free in air (the gases of the air are mixed, not 
chemically combined); in combination it is very abundant. 
It is the most abundant and most widely diffused of all the 
elements, forming more than three-fourths of animals and 
plants, and one-half of the solid part of the earth's crust. 

O is generally prepared from potassium chlorate (KC10 3 ) 
and manganese dioxide (Mn0 2 ). 

To Prepare (). — App. — Large test-tube with rubber cork containing 
a short glass tube, the delivery tube used in preparing H, wide-mouthed 
half 1. bottle (for receiver) with cover, retort stand, lamp, mortar, cru- 
cible, and pneumatic trough. Mat. — 5 g. KC10 3 and 3 g. Mn0 2 . 

Exp. 63.— Arrange to collect the gas over H 2 (as in collecting H). 
Pulverize the CCIO, (see Caution, p. 35) and mix it thoroughly with the 
Mn0 2 ; dry the mixture by heating it gently in the crucible and put it 
into the test-tube, inclining the tube and distributing the mixture nearly 
to its mouth. Cork the tube, attach the delivery tube, and allow the 

free end of this to dip into 
the water, then heat. The 
tube, while being heated, 
may be held in the hand, 
or supported as shown in 
Fig. 13. After the bub- 
bles (air) have escaped for 
a few seconds, collect the 
gas. Continue heating in 
the same place until all 
the is expelled from the 
Fig. 13.— Preparation of 0. mixture directly over the 

flame, indicated by a stop- 
ping of the flow of bubbles. Fill the bottle with 0. Preserve the gas 
for Exp. 64, and put* the tube in the rack to preserve the unused 
material. When more is needed the tube is heated again. 




OXYGEN GROUP. 47 

Reaction, — KC10 3 = 3 + KC1 (potassium chloride). 

In this process the O is obtained from the KC10 3 , the Mn0 2 
acting by catalysis (p. 18). KC1 is soluble and Mn0 2 insolu- 
ble in H 2 0, hence they may be easily separated. 

Exp. 64. — Shake the residue in the tube (when its contents have been 
exhausted of 0) with some H 2 0, and pour the mixture on a filter. The 
solution of KC1 passes through and the Mn0 2 remains on the filter ; 
when dry it may be used again. Obtain crystals of KC1 by evaporation. 

By inverting several bottles in the trough and using a sufficient 
amount of material, for all the experiments may be prepared at the 
same time, or the gas may be more conveniently collected in a gas- 
holder and transferred from this to the bottles for the several experiments. 

Illustrations of the Chemical Energy of O. 

Producing Flame in 0. — App. — Lamp. Mat. — The from Exp. 63, 
and pine splinter pushed through the centre of a disk of pasteboard to 
serve as a temporary cover. 

Exp. 65. — Put the bottle of erect on a table ; light the splinter, and 
when the end glows, blow out the flame and thrust the glowing end into 
the gas. The wood will again blaze. Repeat the experiment again and 
again until the is exhausted. 

Burning of Charcoal in 0. — The App. and Mat. used in preparing 0, 
stout wire with one end bent into a U-shape and the other pushed 
through the centre of a piece of pasteboard, and piece of charcoal (that 
prepared from bark being the best). 

Exp. 66. — Fill the bottle with 0. Fix the C firmly in the U of the 
wire, heat it to glowing and plunge it into the bottle. The C burns 
brightly, throwing off brilliant sparks. C0 2 is formed by the combustion. 

Burning of Sulphur in 0. — App. and Mat. — The generator, etc., 
the U wire with a piece of chalk or crayon containing 
a deep cavity fitted into the bend (or deflagrating spoon, 
p. 143), and piece of S as large as a pea. 

Exp. 67. — Fill the bottle with ; put the S in the 
chalk cavity, light it, and thrust it into the gas. S0 2 
(p. 53) is formed. 

Burning of Phosphorus (P) in 0. — App. and Mat. — - 
The generator, etc., and piece of P as large as a grain 
of wheat. (See Caution below.) 

Caution. — Great care should be taken in using P, as -p -,, s nT _ 

very little friction ignites it and it burns with great R ' T>rj RN _ 

energy. It should be cut under H 2 and handled with ^ 

wet hands. If a piece of P in contact with the hand 
takes fire, quickly plunge the hand into water. 




48 



OXYGEN. 




Fig. 15. — Iron Wire Burning in 0. 



Exp. 68. — Fill the bottle with 0, dry the P with filter paper, put it 
into the chalk cavity, light it, and plunge it into the gas. The intensity 
of the chemical energy produces a brilliant light. P 2 5 (p. 80), the 
dense white fumes, is formed. 

Burning of Iron Wire in 0. — App. and Mat. — The generator, etc., 
substituting for the half 1. bottle a stoppered 1. receiver without bottom 
(p. 143), and piece of light iron wire (or better, piano wire), half of 
which is made into a spiral by wrap- 
ping it on an iron rod or lead pen- 
cil. The coil end of the wire should 
be hammered very thin, and the 
straight end pushed through the 
centre of a piece of pasteboard. 

Exp. 69. — Fill the receiver with 
and remove it on a saucer to the 
table. Fix the friction end of a 
match by means of a slit made in it 
on the coil end of the wire, or dip 
the end into melted S, light the 
match or S and quickly plunge the 
wire into the gas. It burns with a 
dense light accompanied by a shower of sparks. Fe 3 4 , which falls off in 
globulus, is formed. 

Effect op Forced into a Flame. — App. and Mat. — Lamp, blowpipe, 
piece of iron Avire, and in a bottle gas-holder. 

Erp. 70. — Force into the flame from the gas-holder as air is forced 
'nto it in blowpiping, and to test the temperature of the flame, hold the 
iron wire in it. The metal burns with scintillations, like the wire in 0. 

Uses and Tests. 

O is the great life element of animals. From the lungs 
into which it is breathed as a constituent of air, it is taken up 
by the blood and distributed through the body, entering into 
various combinations to nourish the wasted organs and to gen- 
erate heat. Combining readily with combustible matter, it 
plays an important part in heating and illumination. It is 
also the active agent in decay and fermentation. O specially 
prepared for the purpose, is sometimes used for intensifying 
the heat of flames. 

The rekindling of a glowing splinter (Exp. 65) is a toler- 



OXYGEN GROUP. 49 

ably sure evidence of the presence of 0. N 2 (p. 73) is the 
only other gas that will reproduce flame in this way. 

Ozone. 

Ozone is an allotropic (p. 18) form of O, differing atomic- 
ally from O in having three atoms in its molecule (the mole- 
cule of O contains two atoms). 

Ozone has an odor somewhat like that of weak CI. It acts 
with great energy, being a powerful oxidizing agent. It de- 
stroys vegetable colors and is an active disinfectant. 

Occurrence, Preparation, and Test. 

A small quantity of ozone exists in pure air, but more is 
found in the atmospheres of large cities. In air it probably 
acts as a purifying agent. 

Ozone is developed by the action of an ordinary electrical 
machine, and can best be prepared by an electrical machine 
designed for the purpose. It is most conveniently prepared, 
however, bv parti v covering a piece of phosphorus (P) with 
H 2 0. 

To Prepare Ozoxe and Shoav its Presence. — App. — Wide-mouthed 
half 1. bottle with cover. Mat. — Cylinder of P about an in. long (See 
Caution, p. 47) white paper, and mixture of starch paste and solution 
of potassium iodide (KI). 

Exp. 71. — Scrape the P clean and put it into the bottle ; add sufficient 
H 2 to half cover it, cover the bottle and let it stand in a warm place 
for several hours. It will then contain ozone. Test. — Smear the paper 
with the paste mixture and suspend it in the bottle. It quickly be- 
comes blue, the ozone decomposing the KI, the iodine of which colors 
the starch blue. Ozone is produced by the rapid evaporation of certain 
liquids. 

Ozoxe by Evaporation. — Mat. — KI paper and ether (or alcohol). 

Exp. 72. — Let fall a few drops of ether on a piece of the paper and 
set the liquid on fire. After the combustion the paper will be colored 
blue from the formation of ozone. 



50 COMBINING OF OXYGEN AND HYDROGEN. 

Combining of Oxygen and Hydrogen. 

The Oxy-Hydrogen Flame. 

The H flame (Exp. 20) is produced by the union of H with 
O from air. If the O be supplied from a gas holder, a flame 
of much greater intensity, called the oxy-hydrogen flame, is 
produced. This flame quickly burns steel wire, scattering the 
glowing mass in a beautiful shower, and it readily melts plati- 
num and other substances that withstand the heat of the hot- 
test blast furnaces. H 2 is produced by this combustion as it 
is by the ordinary burning of H. 

The Oxy-Hydrogen Blowpipe is an apparatus for producing 
the OH flame. It consists of two tubes, one inside the other. 
The inner tube is connected with an O gas-holder and the 
outer w r ith an H gas-holder. 

To Explode a Mixture of and H. — App. — Soda-water bottle, clay- 
pipe, short glass tube, lamp, and long pine splinter. Mat. — Some of the 
H and mixture in the bottle gas-holder, and some soap-bubble liquid 
(p. 24) in a mortar (or metal vessel). To prepare the gas mixture, pre- 
pare sufficient to reach to a depth of 3 or 4 inches in the bottle, and 
add to it twice as much H. 

Exp. 73. — Fill the soda-water bottle with the mixture by H 2 dis- 
placement, cork the bottle and, holding it in a horizontal position in 
one hand, uncork it, and quickly insert a lighted match into its mouth. 

The mixture will explode. 
Explode a bottle full of the 
gas by lifting the bottle in- 
verted just out of the H 2 
and inserting the lighted 
match. Explode a bottle 
with a light body, as a cork, 
placed just above its mouth. 

Exp. 74. — Inflate soap- 
Fig. 16. — Exploding of H and 0. , , , , .., xl _ 

bubbles with the mixture in 

the same manner as bubbles were inflated with H and have an assistant 

touch them with the lighted splint. (See Caution below). 

Exp. 75. — Replace the pipe by a short glass tube, start the gas, and 

move the tube through the liquid, which will become covered with bub- 




OXYGEN GROUP. 51 

bles. Explode the bubbles by touching them with the lighted splinter. 
(See Caution below). 

Caution. — In making experiments 74 and 75, be very careful not to 
touch the bubbles with the flame until the delivery tube has been re- 
moved a considerable distance from them. 

SULPHUR (S) 32. 

Properties. 

S. has several allotropic forms. Common S is a yellow, 
crystalline solid, which melts at 114° C. and boils at 440°. 
Common S, when heated to boiling and suddenly cooled, be- 
comes dark and soft (plastic sulphur). S is insoluble in H 2 0, 
but dissolves readily in carbon disulphide. It burns with a 
blue flame, S0 2 being formed, (Exp. 83). Compounds of S 
with metals are called sulphides. 

To Prepare Crystals of S. — App. — Cup 2 in. deep cut from the bot- 
tom of a tin fruit can (or an old tea-cup) and lamp. Mat. — J lb. S. 

Exp. 76. — Melt the S in the cup, heating so carefully that it does not 
darken. Then reduce the temperature sufficiently to allow the surface 
of the liquid to harden, and when a thin crust has 
formed, make a hole in it and pour out the liquid S 
remaining. Remove the crust, and the bottom of the 
cup will be found full of crystals. If a porcelain cup 
be used, it may be broken to show the crystals. Crys- 
tals of S may also be obtained from its solution. 
(Exp. 78). 

To Prepare Plastic S. — App. — Small test-tube 
and holder (p. 142), for which a flattened roll of paper FlG - l ^'~ C J YS " 

Vi n l r TALS OP S. 

may be substituted, and lamp. Mat. — 2 g. S and H 2 0\ 

Exp. 77. — Melt the S in the test-tube and continue heating until it 
boils, then pour it into the H 2 0. The dark product, which resembles 
india rubber, is plastic. S. Put a piece of plastic S in boiling H 2 0, and 
preserve another piece for several months. They will change to ordi- 
nary S. 

Dissolving op S in Carbon Disulphide (CS 2 ). — App. — Small test- 
tube and piece of window-glass. Mat. — CS 2 and piece of S as large as 
a grain of wheat. 

Exp. 78.— Put the S and 2 c.c. of CS 2 in the tube, and shake. The S 
dissolves. Pour some of the solution on the glass, and crystals of S 
soon form. 




52 HYDROGEN SULPHIDE. 

Occurrence and Preparation. 

S occurs free in certain volcanic regions. About nine-tenths 
of the S of commerce comes from Sicily. Valuable deposits 
are found in Nevada and Louisiana. It is a constituent of 
many compounds, as hydrogen sulphide, pyrite, and gypsum. 

Native S is freed from earthy impurities by distilling the 
volcanic earth, or, if this be rich in S, by simply heating it 
and separating the melted S from the impurities. 

Uses and Tests. 

The chief consumption of Sis for H 2 S0 4 . A large amount 
is also used in the manufacture of friction matches, gunpowder, 
and vulcanized rubber. S and its compounds have been used 
extensive 1 ]}' of late years for preventing grape disease in the 
vineyards of Europe. 

S is recognized by its color, and when burned, by its odor 
and flame. Combined S may be detected by fusing the com- 
pound (on charcoal with a blowpipe flame) with sodium car- 
bonate, and placing the fused mass on a clean silver coin. 
The coin is blackened. 

Exp. 79. — Test sodium, magnesium, or calcium sulphate for S. 

Hydrogen Sulphide (H«S). 

Properties. 
H 2 S (sulphuretted hydrogen, hydrosulphuric acid) is a col- 
orless gas with the odor of rotten eggs. At ordinary temper- 
atures HoO dissolves more than 3 times its volume of the gas, 
which gives its odor to the solution. It burns with a blue 
flame, H 2 and S0 2 (p. 53) being produced, and is readily 
decomposed by heat. Its action on certain metals produces 
sulphides, and it precipitates many metals as sulphides from 
solutions of their compounds. 

Occurrence and Preparation. 
H 2 S is a product of the putrefaction of organic substances 
containing S, and hence one of the causes of the foul odor of 



OXYGEN GROUP. 53 

sewers. It is a constituent of the waters of "sulphur springs." 
It is generally prepared from HO or H 2 S0 4 and iron sul- 
phide (FeS). 

To Prepare H 2 S. — Test. — App. — Test-tube and piece of filter paper. 
Mat. — | g. FeS, and H 2 0, HC1, and solution of lead acetate. 

Caution. — H 2 S should be prepared in a draft of air or out of doors. 

Exp. 80. — Put the FeS in the tube, cover it with H 2 and add a little 
HC1. H.,S. known by its smell, is given off. The action may be has- 
tened by heating. Test. — Wet the paper with the acetate and cover the 
tube with it. The paper darkens. Write a name on the paper with the 
acetate and expose it to the gas. 

Reaction.— FeS-f 2 HC1 = H 2 S + FeCL (ferrous chloride). 
Illustrations of Properties. 

Dissolving of H 2 S in H 2 0. — App. — Same as that used for generating 
H (p. 23). Mat.— HC1, 3 or 4 g. FeS. and qr. 1. bottle nearly full of H 2 0. 

Exp. 81. — Put the FeS, a little H 2 0, and 2 or 3 c.c. of HC1 in the gen- 
erator, and dip the delivery tube into the bottle* of H 2 0, extending it to 
the bottom. H 2 S water is formed. Continue the action until the H 2 
smells strongly of the gas. Cork the bottle and preserve the solution. 

Burning op H 2 S. — App. — The generator used in Exp. 81, jet tube like 
that used in burning H, and a dry wide-mouthed bottle. Mat. — 2 or 3 
g. FeS and HC1. 

Exp. 82. — Connect the jet tube with the end of the delivery tube and 
generate the gas. After waiting until the air is expelled from the appa- 
ratus, light the jet. To show that H 2 is formed, hold the wide-mouthed 
bottle inverted with the flame within it and moisture will collect upon it. 

Uses and Tests. 
H 2 S is much used in the chemical laboratory in testing for 
and separating metals. It is known by its odor ; a special 
test is its darkening paper Avet with a solution of lead acetate, 
lead sulphide being formed. (Exp. 80) 

Sulphur Dioxide (SO- 2 ). 

Properties. 
S0 2 (sulphurous oxide, sulphurous acid) is a colorless, suf- 
focating gas, very soluble in H 2 0. It extinguishes flame, and 
is a bleaching agent. In bleaching, it does not destroy the 



54 SULPHUR TRIOXIDE. 

color as CI does, but combines with it to form colorless com- 
pounds. Compounds of S0 2 with metallic oxides, etc., are called 
sulphites. 

Preparation, and Illustration of Properties. 

S0 2 is formed by the burning of S in air, as in the kindling 
of a sulphur match. It may be obtained pure by the action 
of strong H.,S0 4 on copper. 

Extinguishing of Flame by S0 2 . — App. — Wide-mouthed half 1. bottle 
with cover, small crucible, wire bent so as to suspend the crucible within 
the bottle, and lamp. Mat. — 2 g. S, tuft of cotton fastened to the end 
of a wire (or pine splinter), and alcohol. 

Exp, 83. — Hold the crucible containing the S by means of the wire in 
the flame until the S kindles, then suspend it in the bottle and put on 
the cover. "When the S flame goes out, remove the crucible, wet the 
cotton with alcohol, light it and thrust it into the gas. The flame is 
extinguished. 

Bleaching with SO r —App. — The crucible used in last experiment, 
an ordinary lamp chimney and lamp. Mat. — 2 or 3 g. of S and a red 
flower. 

Exp. 84. — Support the flower, moistened with H 2 0, in the top of the 
chimney, then heat the S in the crucible until it kindles, put the cruci- 
ble on a piece of metal or porcelain, and cover it with the chimney. 
The flower bleaches. 

Uses and Tests. 
The most important use of S0 2 is in the manufacture of 
H.»S0 4 . It is also used for bleaching straw and woolen fabrics, 
and as a disinfectant. The gas is recognized by its odor, that 
of a burning match. 

Sulphur Trioxide (SO s ). 
SO a (sulphuric oxide) is a white, silky-looking, crystalline 
solid, with so strong an affinity for ELO that the two substances 
combine with a hissing sound, forming H,S0 4 . It may be 
prepared by passing a mixture of S0 2 and O through a heated 
tube containing platinum sponge (p. 92 ) the S0 2 becoming 
oxidized. The fuming product is condensed in a cooled 
receiver. 



OXYGEN GROUP. 55 

Sulphuric Acid (H 2 S0 4 ). 

H 2 S0 4 (oil of vitriol) is a colorless, oily liquid with a sp. 
gr. of 1.82 (sp. gr. of pure acid is 1.84). H 2 S0 4 is very cor- 
rosive, quickly charring wood and other organic substances, 
and is intensely acid, reddening litmus paper when diluted 
with a thousand times its volume of H 2 0. It unites with 
H 2 with great energy, producing much heat. Commercial 
H 2 S0 4 contains lead sulphate formed from the leaden vessels 
used in the manufacture of the acid, is often colored brown 
by dust or other matter, and always contains some ILO. 
Compounds formed by the action of H 2 S0 4 on metals, etc., 
are called sulphates* 

Corrosiyeness and Acidity op H 2 S0 4 . — App. — Glass rod, and strip of 
blue litmus paper. Mat. — Pine splinter, piece of white paper, H 2 SO^ 
andH 2 0. 

Exp. 85. — Dip the splinter into the H 2 S0 4 . It quickly blackens. 
Write on the paper with dilute H 2 S0 4 and heat the writing. 

Exp. 86.— Stir a drop of H 2 SQ 4 in 10 c.c. of H 2 and dip the blue 
paper in the liquid. The paper reddens. 

Production of Heat by the Combining op H 2 S0 4 and H 2 0. — Mat. — 
60 c.c. strong H 2 S0 4 , 30 c.c. H 2 in a beaker, and 2 or 3 c.c. alcohol in 
a test-tube. 

Exp. 87.— Pour the H 2 S0 4 slowly into the H 2 (H 2 S0 4 and H 2 should 
always be mixed in this way) and stir the mixture with the test-tube. 
The alcohol will boil. 

To Show that H 2 S0 4 Contains Lead Sulphate (PbS0 4 ).— Mat.— 20 
c.c. strong H 2 S0 4 and 100 c.c. H 2 in a beaker. 

* Vinegar was the strongest acid known to the ancients. Sulphuric 
acid is said to have been obtained by Geber, an Arab, in the eighth 
century, by distilling alum. It was certainly obtained by Basil Valen- 
tine, a monk of Erfurt, about the year 1440., by distilling green vitriol. 
Valentine also made the first steps in the discovery of the present pro- 
cess of manufacturing the acid, which process possessed all its essential 
features when Dr. Roebuck, of England, introduced the leaden cham- 
bers in 1746. Since the production and use of this acid are so universal, 
it has been suggested that the extent of its manufacture may be regarded 
as a measure of the material prosperity of a country. Nitric acid was 
known to Geber. who called it solutive water. It was distilled from salt- 
petre (Exp. 131) mixed with clay, etc., in the thirteenth century. 
Hydrochloric acid was occasionally produced at an early date by heating 
a mixture of common salt and clay ; its manufacture from salt and 
H 2 S0 4 (Exp. 48) began about the year 1789. 



56 



SULPHURIC ACID. 



Exp. 88. — Add the H 2 S0 4 to the H 2 and let the mixture stand several 
hours, when the precipitate of PbS0 4 will be found at the bottom of the 
beaker. 

Occurrence and Preparation. 
H 2 S0 4 is found in the waters of certain springs and rivers 
in volcanic regions. Its compounds (sulphates, as gypsum) 
are abundant. H>S0 4 is formed by the union of 80 3 and 
H 2 0. 

To Show How H 2 S0 4 is Formed. — App. — Wide-mouthed 1. bottle, 
small crucible with suspending wire, and lamp. Mat. — 2 g. S, shaving 
attached to the end of a wire, HN0 3 , and blue litmus paper. 

Exp. 89. — Burn the S in the bottle as in Exp. G7 and put the shaving 
wet with HN0 3 into the S0. 2 formed. is transferred from the HN0 3 to 
the S0 2 , the action being indicated by the reddish fumes of N0 2 . Add 
a little II 2 and shake the bottle. The liquid is dilute H 2 S(.) 4 . Prove 
its acidity. 

The chemical process involved in the manufacture of H 2 S0 4 
is similar to that explained by the last experiment. It is 
shown by Fig. 18. A is a large chamber lined with sheet 
lead and containing a little H 2 0. Entering this chamber is a 




-Manufacture of I1 2 S0 4 . 
stream of SO, produced by heating S, or generally iron pyrite 
(FeS 2 ) in the furnaces CC; HNO., vapor produced from 
sodium nitrate and H. 2 S0 4 contained in an iron crucible heated 
by the S0 2 ; and steam from the boiler B. 

The reactions are thus explained : NO produced from the 
HN0 3 unites with O, the union forming N0 2 . This gives a 



OXYGEN GROUP. 57 

portion of its O to S0 2 , the union forming S0 3 which unites 
with H 2 0, the union forming H 2 S0 4 ; the jSTO unites with 
another portion of O and the action continues. The H 2 S0 4 , 
very dilute, forms on the bottom of the chamber. It is con- 
densed by evaporation to the requisite density. 

Uses and Tests. 

H 2 S0 4 is one of our most useful products. It is used in 
the chemical laboratory, in preparing other acids, bleaching 
compounds, artificial fertilizers, etc., in refining petroleum, 
and for many other purposes. 

H 2 S0 4 is known by its charring organic substances, and a 
test for the acid, either free or in one of its salts, is the pro- 
duction of a heavy white precipitate with barium chloride 
(BaCL). The precipitate is insoluble in H 2 and dilute acids. 

Exp. 90. — Add a solution of BaCl 2 to very dilute H 2 S0 4 , also to a so- 
lution of sodium sulphate. White precipitates are produced. Try to 
dissolve them. 

The other elements of the S group, which are quite rare, are 
closely allied to S. Selenium possesses the peculiar property 
of undergoing a change in its power of conducting electricity 
by the action of light. Selenium and Tellurium occur both 
free and combined. 



PRACTICAL QUESTIONS. 

1. Name some compounds containing 0. Some that do not con- 
tain 0. 

2. What is the weight of a litre of ? A gallon ? 

3. How much can be prepared from 10 g. of KC10 3 ? 

4. How much KC10 3 would be required to produce 10 g. of 0? To 
produce 1 litre ? 

5. What other questions may be asked concerning the reaction (p. 47) ? 

6. The reaction in the preparation of from HgO (mercuric oxide) is 
expressed thus : 

HgO=Hg + 



58 CALCIUM OXIDE. 

How do the weights of prepared from equal weights of KC10 3 and 
HgO compare with each other ? 

7. On what does the amount of needed by the system depend? 

8. During what season of the year do we consume the greatest amount 
of 0? The least amount ? Why? 

9. What effect would be produced by breathing instead of air? 

10. Why is fruit preserved by canning? Why by drying? 

11. Why is S used on the ends of friction matches? 

12. Cu -f- H 2 S=? Explain the reaction. 

13. Why is H 2 S0 4 blackened by organic matter ? 

14. How much H 2 S0 4 is required to dissolve 100 lbs of Zn? 

15. What weight of S must be burned to make 100 litres of H 2 S0 4 ? 
What weight of FeS 2 ? 

CALCIUM GROUP. 

CALCIUM, BARIUM, STRONTIUM, LEAD. 

The elements of this group are dyads. The oxides of the 
first three are the so-called alkaline earths. 

CALCIUM (Ca) 40. 
Ca is a reddish, soft, malleable metal, which quickly oxi- 
dizes in moist air and decomposes H 2 0. Its compounds, the 
most abundant of which is calcium carbonate (limestone, etc.) 
are widely diffused. 

Calcium Oxide (CaO). 

CaO (lime, quicklime) is a white, amorphous, strongly alka- 
line solid. It combines with H 2 with great energy (slacks) 
producing much heat. The product is calcium hydrate. It 
absorbs moisture from the air and crumbles to powder (be- 
comes " air slacked ") which gradually absorbs C0 2 . 

Slacking of CaO. — App. — Small tin lid. Mat. — Lump of CaO as 
large as a walnut and H 2 0. 

Exp. 91. — Put the CaO on the lid and pour on it 20 or 30 c.c. of H 2 0. 
It increases greatly in bulk and temperature. To test the heat support 
the lid on the hand and light a match against the slackening CaO. 

CaO is prepared by intensely heating limestone (CaCO s ) in 
large kilns or piles. The process is called " burning lime." 



CALCIUM GROUP. 59 

The C0 2 is driven off and CaO remains. CaO is used as a 
fertilizer, as a flux in metallurgy, as an ingredient of mortars 
and cements, in the manufacture of bleaching powders, and 
for other purposes. Hydraulic cement, which hardens under 
H 2 0, is either lime obtained from limestone containing from 
15 to 35 per cent, of clay, or a prepared mixture of ordinary 
lime and clay. 

Ca Hydrate (CaS a Oj, Ca Chloride (CaCLJ. 

CaH 2 2 (slacked lime) is a white alkaline powder slightly 
soluble in cold H 2 and more soluble in cold than in hot 
H 2 0. The solution is lime-water. White ivash is a mixture 
of CaH 2 2 and H 2 0. Bleaching powder (chloride of lime), 
which is regarded as a mixture of calcium chloride and cal- 
cium hypochlorite, is a white powder used in large quantities 
for bleaching. It is prepared by passing CI through recently 
slacked lime. 

CaCl 2 is a white deliquescent salt, prepared by dissolving 
calcium carbonate in HC1. It is used for drying gases. 

Calcium Carbonate (CaC0 3 J. 

CaC0 3 (limestone, chalk, marble, etc.) varies in color and 
varies greatly in structure ; marble is white and crystalline, 
■while ordinary limestone is generally blue" or gray. Crystal- 
line CaC0 3 has a great variety of forms. CaC0 3 is soluble in 
dilute acids and in H 2 charged with C0 2 . The white pre- 
cipitate which often forms in mineral waters exposed to air is 
due to the precipitation of CaC0 3 by reason of the escape of 
C0 2 . 

CaC0 3 occurs in nature as limestone, chalk, marble, coral 
reef, etc. Shells are largely CaC0 3 ; whiting is ground chalk. 
Stalactites and stalagmites are conical masses of CaC0 3 found 
in caverns, the former hanging like icicles from the roof of 
the cavern, and the latter projecting from the bottom. They 
are formed by H 2 0, charged with C0 2 and holding CaC0 3 in 
solution, trickling through the rocks ; C0 2 escapes and CaC0 3 
is deposited. 



60 BARIUM, STRONTIUM. 

Calcium Sulphate (CaSOJ. 
CaS0 4 is a white mineral occurring in both a crystalline 
and an amorphous condition. The hydrated amorphous 
variety, CaS0 4 -f 2 ELO, is known as gypsum or plaster. CaS0 4 
is soluble in about 400 times its weight of cold H 2 0. Gypsum, 
when heated, gives up its H..O, and if heated to about 120° C. 
forms a dry product called plaster of Paris, which when made 
into a paste with H 2 0, recom bines with the H 2 and becomes 
hard. This property renders the substance useful for making 
casts, ornamental designs, etc. Gypsum is much used as a 
fertilizer. A variety called alabaster is cut into vases, boxes, 
etc. Calcium sulphate is widely distributed and very abundant. 

Calcium Phosphate (Ca,P 2 O s ). 

G^P.O^ is the chief earthy material of bone, and forms a 
valuable constituent of the grains of cereals. It also occurs 
in rocky masses, in North Carolina and other places. It is a 
valuable fertilizer, forming the most important ingredient of 
guano and phosphatic fertilizers. 

Exp. 92. — Heat a fragment of CaC0 3 on charcoal until CaO is formed. 
Prepare CaCl and CaS(> 4 . 

BARIUM; (Ba), STRONTIUM, (Sr). 

These are rare metals which closely resemble Ca, and most 
of their compounds are closely analogous to Ca compounds. 
The salts of Ba color a flame green, and those of Sr, crimson, 
hence the extensive use of these salts in pyrotechny. Barium 
sulphate, which is sometimes found as a heavy white mineral, 
is used for adulterating white lead. 

Colored Fires. — App. — A brick (or piece of earthenware). Mat. — 
2 g. barium nitrate (BaN0 3 ), 2 g. strontium nitrate (SrN0 3 ). 1 g. po- 
tassium chlorate (KC10 3 ) and 1 g. gum shellac (or charcoal) ; these 
must be finely pulverized and very dry. 

Exp. 93. — Green fire. Mix thoroughly with care, the BaN0 3 , half the 
KC10 3 . and half the shellac, put the mixture on the brick, and set it on 
fire with a match. The burning of the shellac (carbon) is sustained by 
the of the nitrate and chlorate, and the Ba produces the green color. 



CALCIUM GROUP. 61 

Exp. 94. — Red fire. Mis the SrN0 3 with the remainder of the KC10 3 
and shellac ; and set the mixture on fire. The action in burning is the 
same as that in producing green fire. 

LEAD (Pb) 206.9. 

Pb is a bluish-white, malleable metal, and so soft that it 
can be easily eat and indented. Sp.gr. 11.5. When freshly 
cut, it has a bright lustre which it soon loses by oxidation. 
Natural waters act upon Pb ; those, however, containing car- 
bonates, sulphates, or phosphates, have but little action on it. 
Since the salts of lead are poisonous, the conveyance of water 
for household purposes through lead pipes is often dangerous. 
Water that has been standing in lead pipes should not be used 
for drinking or culinary purposes. Pb is slightly acted on by 
cold HC1 and H 2 S0 4 ; it is soluble in HXO^ 

Pb is rarely found free in nature. Its most abundant ore is 
the sulphide (PbS, Galena) from which it is generally obtained 
by roasting the ore in an opened reverberatory furnace, and 
then heating it to a higher temperature with the furnace 
closed. Pb is used for water pipes, for the chambers employed 
in the manufacture of H 2 S0 4 , and various other purposes. 
It is an ingredient of several alloys: common solder and pew- 
ter are Pb and tin ; type-metal, Pb and tin, or Pb, tin, and 
antimony. 

Exp. 95. — Find the sp. gr. of Pb (p. 133.) Exp. 96. — Test the solu- 
bility of Pb in acids. 

Compounds. 

Lead monoxide (PbO, litharge) is a reddish or yellowish 
powder, generally prepared by heating Pb in air. It is used 
as an ingredient of flint glass and in the preparation of paint. 
Lead dioxide (Pb0 2 ) is a brown powder prepared by oxidizing 
litharge. Eed lead (minium) is a mixture of PbO and PbO,. 
Lead sulphide (Galena) is artificially produced as a black or 
brown precipitate by passing hydrogen sulphide into solutions 
of Pb. Lead acetate (sugar of lead) is a white, poisonous salt, 
soluble in H 2 0. Lead silicate is an important ingredient of 



62 MAGNESIUM. 

flint glass. White lead is a mixture of lead carbonate and 
lead hydrate. It is prepared in large quantities for paint by 
the action of vinegar on sheet lead in jars covered with spent 
tan. The lead acetate first formed is converted into a carbon- 
ate by the action of C0 2 from the decomposing tan. The 
disease called painter's colic is due to the slow action of lead 
carbonate. Epsom salt is an antidote for lead poisons. 
Tests. 

Pb compounds yield Pb when fused with sodium carbonate 
on charcoal. H 2 S0 4 produces in solutions of salts of Pb a 
white precipitate of lead sulphate. 

Exp. 97. — Obtain a globule of Pb from lead acetate. Dissolve it in 
HNO a and add H. 2 S0 4 . 

MAGNESIUM GKOUR 

MAGNESIUM, ZINC, CADMIUM. 

The elements of this group are dyads. Each of them has 
only one oxide and one sulphide. 

MAGNESIUM (Mg) 24. 

Mg is a silver-white metal which tarnishes in air, and when 
heated, burns with great brilliancy. It dissolves in the com- 
mon acids. Mg is not found free in nature, but is widely 
diffused as a constituent of a variety of minerals and of nat- 
ural waters. The salts of Mg give water a bitter taste. Mg 
is generally prepared by heating magnesium chloride with 
sodium. It is used as a source of light, for which purpose it 
is sold in the form of ribbon or wire. 

To Show the Mg Light. — App. Lamp and pincettes. Mat. — 2 or 3 
in. Mg ribbon. 

Exp. 98. — Make this experiment if possible in a darkened room. 
Hold one end of the ribbon by means of the pincettes in the flame, and 
the metal will soon burn. The white ash is MgO. 

Compounds. 

Magnesium oxide (MgO, magnesia) is a white, infusible pow- 
der formed when Mg burns in air. Magnesium carbonate 



MAGNESIUM GROUP. 63 

(MgC0 3 ) occurs as a mineral and is also prepared. Magnesium 
sulphate (MgS0 4 ) is a white salt soluble in H 2 0. Its solution 
produces crystals called Epsom salt (MgS0 4 + 7 H 2 0) which 
is found in many mineral waters. Magnesia alba is a mixture 
of the carbonate and hydrate (MgH 2 2 ). It is prepared by 
adding sodium carbonate to a hot solution of MgS0 4 . 

Exp. 99.— Prepare MgS0 4 -f- 7 H 2 from H 2 S0 4 and MgC0 3 . Prepare 
also magnesia alba. 

ZINC (Zn) 65. 

Zn is a bluish-white, hard, crystalline metal. It is brittle 
at ordinary temperatures and at temperatures above 200° C, 
but malleable at from 100° to 150°, which property renders it 
capable of being rolled into sheets. It tarnishes in moist air, 
and when strongly heated burns with a greenish- white flame. 
It readily dissolves in dilute acids, and precipitates many 
metals from solutions of their salts. 

Exp. 100. — Show the burning of Zn by heating a bit of the metal 
in a blowpipe flame. Exp. 101. — Test the solubility of Zn in acids. 

The Lead Tree. — Mat. — Solution of lead acetate in a small beaker 
(or wide-mouthed bottle), and strip of Zn. 

Exp. 102. — Brighten the Zn, bend it into aU-shape, and suspend it in 
the solution by means of a pencil or match placed across the top of the 
beaker. Allow the beaker to stand undisturbed for several hours. Pb 
forms on the Zn in metallic flakes, the enlarging mass resembling a 
vegetable growth. In this action the Pb and Zn change places, zinc 
acetate being formed, and the weights of Zn dissolved and Pb precipi- 
tated are proportional to the atomic weights of these elements. 

Zn is not found free in nature, but its ores are quite abund- 
ant. The most important of these are the sulphide (blende), 
carbonate (calamine) and oxide (red oxide). The metal is 
obtained from its ores by roasting them and then heating the 
product, zinc oxide, with charcoal, when Zn is set free, and 
collected in a receiver. 

Zn is used for coating (galvanizing) iron, for the plates of 
voltaic batteries, and, in the form of sheets, for various pur- 
poses. It is used also as an ingredient of brass and German 
silver. 



64 aluminum:. 

Compounds, 

Zinc oxide (ZnO) is an ore, and is also prepared in the form 
of a light white powder by burning Zn vapor at the mouth 
of the furnaces in which the ores are reduced. It is much 
used as an ingredient of white paint. Zinc chloride (ZnCL) is 
a white deliquescent substance prepared by dissolving Zn in 
HC1. It is used in soldering, preserving anatomical speci- 
mens, etc. Zinc sulphate (ZnS0 4 ) is prepared by dissolving 
Zn in H3SO4. Its solution produces crystals called white vit- 
riol (ZnSO, 7 HX)). It is used in medicine and in dyeing. 

E fJl . 103.— Prepare ZnO. ZnCl, and ZnS0 4 + 7 H. 2 0. 
Cad mi urn is a bluish-white metal found in certain Zn ores. 
Its oxides and hydrates resemble those of Zn. The sulphide 
is much used as a yellow paint. 

ALUMINUM GROUP. 

ALUMINUM. INDIUM, GALLIUM. GLUCINUM, CERIUM, DIDYMIUM, LANTHANUM. 

ALUMINUM (Al) 27. 
Al is a bluish-white, very light, sonorous metal. It is not 
found free in nature, but as a constituent of clay, slate, marl, 
and many other compounds, is very abundant. It has been 
too expensive for many uses to which it is adapted, but by 
reason of an improved process of preparing it recently dis- 
covered, its cost will doubtless be greatly reduced and its uses 
increased. It has been employed mainly in making certain 
philosophical instruments, and as an ingredient of aluminum 
bronze (Al and copper) a hard golden alloy, of which much 
cheap jewelry is made. 

Al Oxide (Al 2 3 ), Al Hydrate (Al 2 H«OJ. 

A1 2 3 (alumina) occurs native, as corundum, of which the 
ruby and sapphire are varieties ; and in an impure form, as 
emery. It may be prepared as a white powder by heating 
ammonia alum. 

AUH 6 6 is a white gelatinous mass, which may be obtained 



ALUMINUM GROUP. 65 

by adding (XH 4 )HO to a solution of alum. It combines with 
certain organic coloring substances, producing lakes which are 
used as pigments, and which in dyeing are formed within the 
fibres of, the material. 

To Prepare Logwood Lake. — Mat. — Solution of extract of logwood 
and solution of alum in test-tubes, and (NELJHO. 

Exp. 104. — Mix the solutions and add (XH 4 )HO. Logwood lake is 
precipitated. Prepare also carmine lake. 

Aluminum Sulphate (Al 2 (SG 4 )J. 

A1 2 (S0 4 ) 3 is a white crystalline substance. It is prepared 
on a large scale by heating clay with H 2 S0 4 and from the 
aluminum sulphate and silica (alum cake) formed, dissolving 
out the sulphate with H 2 0. It is used as a source of other Al 
compounds and in dyeing. 

Alum. — The term alum is applied to a group of double 
salts which are crystal lizable and soluble in H. 2 0. The two 
common alums — ammonia alum (A1 2 (S0 4 ) 3 — (NH 4 ) 2 S0 4 -j- 24 
H 2 0) and potash alum — are manufactured in large quantities 
from a slaty clay by roasting it, leaching the roasted mass 
with H 2 0, and adding, after concentration, potassium or 
ammonium sulphate. The alum crystallizes from the solu- 
tion. Alums are used extensively as mordants in dyeing. 

Aluminum Silicate, 

Aluminum Silicate occurs combined with other silicates in 
various minerals, and forms the chief ingredient of clay, 
which contains also silica, iron, and other substances. The 
plasticity of clay when moist, and the hardness it assumes 
when heated, render it a highly valuable material. 

Bricks, earthenware, and common pottery, are made of clay rendered 
plastic with H 2 0, then moulded, dried, and intensely heated. Earthen- 
ware is glazed by dipping the article into a readily fusible mixture (one 
of the principal ingredients of which is generally lead oxide), drying 
and reheating it. Porcelain, which is distinguished from earthenware 
mainly by its compactness and translucency, is made of kaolin, a very 
pure clay, and is glazed with powdered feldspar. The red color of 
bricks and common pottery is due to iron contained in the clay. 



66 COPPER. 

The other elements of the Al group are rare. Indium is 
softer than lead. "When heated it gives a violet-blue flame. 
It is found in the zinc blende of Freiberg. Gallium possesses 
the remarkable property of melting at 30.1° C, and remain- 
ing liquid when its temperature falls considerably below the 
melting point. It is found in zinc ores. Glueinum, also called 
beryllium (Be), resembles aluminum. It is found in a few 
rare minerals. Its salts have a sweet taste. 



COPPER GROUP. 

COPPER, MERCURY. 

COPPER (Ou) 63. 

Cu is a reddish, tenacious, very malleable, ductile metal, 
and one of the best conductors of heat and electricity. Sp. 
gr. 7.9. Its vapor burns with a characteristic green flame. 
At ordinary temperatures it is only slightly affected by air or 
by most acids. Its best solvent is dilute HN0 3 . 

Cu occurs free in nature, and it is sometimes found in large 
masses, as in the Lake Superior region. Its most important 
ore is copper pyrites (CuFeS 2 ) which is widely distributed. 
By a process of roasting and melting, the iron is separated 
from the ore, and copper subsulphide remains ; Cu is obtained 
from this by heating it in a current of air. Cu is used for 
various domestic utensils, for wires to conduct electricity, for 
coating the bottoms of ships, and other purposes. It is an in- 
gredient of brass (Cu and zinc), German silver (Cu, zinc, and 
nickel), bronze, gun-metal and bell-metal (Cu and tin), and 
other alloys.* 

*The very early eras of the human race were denoted by the sub- 
stances used for domestic implements, and were called ages, as the " age 
of stone." the a age of iron," etc. The age of copper followed that of 
stone and preceded that of iron, which fact shows that copper was 
known at a very remote period. Tin must also have bee.i long known, 
since it is found alloyed with ancient copper. 



COPPER GROUP. 67 

Oxides of Copper. 

Copper suboxide (Cu,0, cuprous oxide) occurs in nature in 
ruby-red crystals, and is also prepared. It is used to color 
glass red. Copper monoxide (CuO, cupric oxide, black oxide) 
is a black powder prepared by heating Cu in a current of air, 
or by roasting the nitrate. It is used to color glass green. 

To Form Cu 2 and CuO. — App. — Lamp and light wire 6 in. long. 
Mat. — Copper cent and H 2 0. 

Exp. 105. — Hold the cent in the flame by means of the wire clamped 
tightly around its edge, and when it becomes quite hot put it in the 
H 2 0. It is covered with red Cu 2 0. Hold it again in the flame, keeping 
it in the outer (oxidizing) part, and the Cu 2 changes to black CuO. 

Copper Sulphate (CuS0 4 ), Copper Acetate. 

CuS0 4 is formed by dissolving Cu in hot H 2 S0 4 , or CuO in 
dilute H 2 S0 4 . Its solution produces crystals called blue vitriol, 
(CuS0 4 + 5 H 3 0) the blue color of which is due to the H 2 0. 
Blue vitriol is used in calico printing, and for various other 
purposes. 

To Show that the Color op Blue Vitriol is Due to H 2 0. — App. — 
Crucible lid, pincettes, mortar, and lamp. Mat. — 1 or 2 g. blue vitriol. 

Exp. 106. — Powder the vitriol and heat it on the lid. It will become 
white. Now add a few drops of H 2 and the color will reappear. 

Copper acetate (verdigris), is prepared by packing plates of 
Cu between woolen cloths soaked in vinegar. The term ver- 
digris is sometimes incorrectly used to designate the green 
carbonate that forms on Cu exposed to moist air. 

Exp. 107.— Find the sp. gr. of Cu. Exp. 108.— Test the solubility of 
Cu. Exp. 109.— Prepare CuS0 4 + 5 H 2 0. 

Tests. 

Cu is known by the color which it gives to a flame. Am- 
monium hydrate produces in solutions of Cu a light green 
precipitate, which dissolves in excess of the hydrate, the liquid 
becoming deep blue. Clean iron placed in a solution of Cu is 
quickly coated with the metal. 

Exp. 110. — Hold a piece of light Cu wire in a flame. Exp. 111. — Add 



68 MERCURY. 

(XH 4 ) HO to a solution of copper sulphate. Exp. 112. — Dip a knife blade 
or nail wet with HC1 into a solution of blue vitriol to which a little 
II CI has been added. 

MERCURY (Hg) 200. 

Hg is a silver-white, lustrous metal, and the only metal 
liquid at ordinary temperatures. Sp. gr. 13.6. It freezes at 

40° G, becoming a malleable and ductile solid. Pure Hg 

does not change in air at ordinary temperatures. Hg dissolves 
readily in HNO„ 

Small quantities of Hg are found free in nature. Its prin- 
cipal ore is the sulphide (HgS, cinnabar; which occurs most 
abundantly in California, Spain, and Austria. More than 
half the entire amount of the metal consumed is supplied by 
California. Hg is obtained by roasting the HgS, the S of 
which combines with O, the anion forming S0 2 , and the Hg 
vapor is condensed. Hg is used in the construction of certain 
meteorological and other scientific instruments, in extracting 
gold and silver from their ores, as an ingredient of the amal- 
gam of looking-glasses, and as a source of Hg compounds. 

Compounds. 

Mercury monoxide (HgO, mercuric oxide, red precipitate) is 
a red crystalline powder or yellow amorphous powder. The 
former may be prepared by heating Hg in air. HgO is the 
compound from which was first obtained. Mercurous chlo- 
ride (Hg 2 Cl B , calomel) is a white crystalline powder, insoluble 
in H 2 0. It may be prepared by heating a mixture of HgCl 2 
and Hg. It is much used in medicine. Mercuric chloride 
(HgCL, corrosive sublimate) is a white, crystalline, very pois- 
onous solid, soluble in H 2 0. Its best antidote is the white of 
eggs, with which it forms an insoluble compound. It is pre- 
pared by heating a mixture of mercuric sulphate and com- 
mon salt. It is used to prevent the decay of specimens in 
natural history. 



NITROGEN GROUP. 69 

Tests. 

Hg salts yield Hg when heated with dry sodium carbonate. 
The metal is deposited upon copper placed in solutions of its 
salts. 

Exp. 113. — Heat a little HgCl 2 with some dry sodium carbonate in a 
small test-tube. Globules of the metal form on the sides of the tube. 

Exp. 1 14. — Put a piece of brightened copper wire in a solution of 
HgCl 2 , and when it becomes covered with a white coating (Hg), drv it, 
and heat it in a piece of glass tubing. Globules of Hg form on the 
glass. 

NITEC-GEN GEOTTP. 

NITROGEN, PHOSPHORUS, ARSENIC, ANTIMONY, BISMUTH, VANADIUM, 
URANIUM, COLUMBIUM, TANTALUM. 

The elements of this group generally act as triads or pen- 
tads. The chemical energies of the first five are, broadly con- 
sidered, inversely as their atomic weights. 

NITROGEN (N) 14. 

Properties. 

N is a transparent, colorless, odorless gas, a little lighter 
than air. It does not burn, extinguishes flame, and destroys 
life by suffocation. It is characterized by weak affinities, and 
hence many of its compounds, as gunpowder, nitro-glycerine, 
etc., are very unstable. 

Occurrence and Preparation. 

N is abundant. It constitutes four-fifths of the volume of 
air, is one of the chief constituents of animal substance, is 
present in vegetable substance, and forms a part of many in- 
organic compounds. It is generally prepared by burning the 
O from a confined portion of air with phosphorus (P). 

To Prepare N. — App. — Wide-mouthed 1. bottle, short cork that will 
easily slip inside of the bottle, small piece of chalk containing a cavity 
(or a small crucible), and saucer (or other shallow vessel). Mat. — Piece 
of P twice as large as a grain of wheat (see Caution, p. 47) and H 2 0. 



70 AMMONIA. 

Exp. 115. — Put H 2 in the saucer, place the cork upon it, and sup- 
port the chalk on the cork ; then put the P in the cavity, light it, and 
quickly cover it with the bottle. A few bubbles of air will at first be 
driven out by the heat, but H 2 will soon begin to rise, and will finally 
occupy a part of the bottle equal to the volume of the consumed. 
The white fumes of P 2 5 (p. 80) become absorbed by the H 2 0, and N 
in an impure state remains. Preserve the N in the inverted bottle for 
Exp. 116. 

Extinguishing Flame by N. — App. — Tuft of cotton fastened to one 
end of a wire (or pine splinter). Mat. — The N from Exp. 115, and 
alcohol. 

Exp. 116. — Cover the bottle containing N, leaving the H 2 in it, and 
put it erect on the table ; wet the cotton with alcohol, light it, and 
thrust it into the gas. The flame is extinguished. 

Uses and Test. 
The N of air serves to dilute the O and render it less ener- 
getic, since in respiration, combustion, and other processes 
none of the N of the utilized air enters into combination. 
Free N is known by its chemical inertness. 

Ammonium (NH 4 ). 
The radical called Ammonium, which is regarded as a metal, 
has not been isolated, but is supposed to exist from a resem- 
blance of the structure of compounds into which NH 3 enters 
to the structure of the compounds of potassium and sodium. 
Thus : 

NH 3 + HC1 = NH 4 C1 (like NaCl and KC1). 

Ammonia (NSQ, (JVH 4 ) Hydrate (JV35QJTO. 

Properties of XH 3 . 
NH 3 is a transparent, pungent, strongly alkaline gas, much 
lighter than air. It is very soluble in H 2 0, one volume of 
H,0.at 0° C. dissolving more than 1000 volumes of the gas. 
This solution is called ammonium hydrate (ammonia water, 
aqua ammonia, solution of ammonia, (KH 4 )HO) and exhibits 
the properties of the gas. NH 3 readily changes red litmus 
paper blue, and neutralizes the most powerful acids. By 



NITROGEN GROUP. 



71 



pressure and cold, ]SH 3 may be condensed to a liquid, which 
will rapidly evaporate, producing great cold. 

Dissolving op NH 3 in H 2 0. — App. — Half-1. flask, test-tube that will 
slip inverted into the flask, bit of red litmus paper, retort stand with 
wire gauze, and lamp. Mat. — (NH 4 )H0 and large beaker of H 2 0. 

Exp. 117. — Support the flask inverted in a ring of the stand, and 
stick with H 2 the litmus paper on 
its mouth. Put about 10 c.c. of 
(XH 4 )HO in the tube, support the 
tube on the gauze as shown in Fig. 
18, and heat. NH 3 is driven from its 
solution into the flask. When the 
flask is full, indicated by the color of 
the paper changing to blue, remove it 
carefully, and dip its mouth into the 
H 2 in the beaker. The H 2 will 
absorb the gas and rise, finally nearly 
filling the vessel. 

Neutralization op an Acid by 
NH 3 . — App. — Beaker, stirring rod, 
narrow strip of blue litmus paper, 
and piece of broadcloth. Mat. — 
H 2 S0 4 ,(NH 4 )HO, and H 2 0. 

Exp. 118. — Put some H 2 in the beaker, add to it a few drops ol 
H 2 S0 4 , and stir. Touch the liquid with one end of the paper, and the 
color will change to red. Add a few drops of (NH 4 )HO, stir, and test 
again (tear off the paper that has been in the liquid), and continue the 
operation until the paper is no longer reddened. Ammonium sulphate 
is produced. 

Exp. 119. — Drop H 2 S0 4 on the cloth. Red spots are made where the 
acid touches it. Add (NH 4 )HO and the color is restored. H 2 S0 4 spots 
may be removed from clothing in this way. 




Fig. 



18. — Dissolving of NH 3 
H 2 0. 



Occurrence and Preparation. 
NH 3 occurs in small quantities in air. It is a product of 
the decomposition of organic matter containing N, and was 
formerly produced by the distillation of animal refuse, as 
hoofs, horns, etc. The name "hartshorn" was given to it 
from the fact that horns of the deer were often distilled to 
produce it. The chief source of commercial ammonia is the 



7:> AMMONIUM COMPOUNDS. 

ammoniacal liquor of gas-works. This is the liquid produced 
by passing the illuminating gas, in purifying it, through H 2 0. 
KH :! is conveniently prepared from ammonium chloride 
(NH,C1) and slacked lime (CaH.0,). 

To Prepare NH 3 and (XH 4 )HO. — App. — Qr.-l. flask with cork and 
delivery tube, retort stand, lamp, and mortar. Mat. — 5 g. NH 4 C1, 10 g. 
freshly slacked lime, and U.,0 in a small bottle. 

Exp. 120. — Powder the NH 4 C1 and CaH 2 2 . mix them together, put 
the mixture into the flask and heat gently. NH 3 , knoAvn by its smell. 
is given off. Exp. 121. — Support the flask, arrange to pass NH 3 through 
the H 2 in the bottle, and heat. (NH 4 )HO is produced. 

Reaction — 2 N 1 1 ,C1 CaH 2 2 = 2 NH 3 -f 2 H 2 + CaCL 

(calcium chloride). 

Uses. 

I NH 4 )HO is a valuable laboratory reagent, and is employed 
in the preparation of many commercial products, as sodium 
carbonate, indigo, and the aniline colors. Liquid NIL is 
used in the manufacture of ice. 

Ammonium Chloride (WH 4 CV). 

NH 4 C1 (sal ammoniac) is a white crystalline salt, very sol- 
uble in 11,(). It is prepared in large quantities by neutraliz- 
ing the ammoniacal liquor of gas-works with HC1. It is used 
in soldering, dyeing, and as a source of other NH 4 compounds. 

XII 4 C1 Fumes. — App. — Two beakers (or tumblers) with rims of the 
same diameter. Mat. — (NH 4 )HO and HC1. 

Exp. 122. — Rinse out one beaker with HC1, the other with (XHJ 
llo and invert the acid beaker on the other, fitting the mouths together. 
The vessels will fill with XH 4 C1 fumes. Uncork the (NH 4 )HO and IIC1 
bottles, and bring their mouths near together, and the fumes will also 
appear. 

Other XH 4 Compounds, 

Ammonium carbonate of commerce is a white, fibrous sub- 
stance, with a strong smell of NH 3 . It is prepared either by 
heating NH 4 C1 with calcium carbonate, or by the dry distilla- 
tion of animal substance, as bone and horn. There are sev- 
eral ammonium carbonates. Ammonium nitrate (NH 4 )X0 3 , 
is a white crystalline salt, very soluble in H.,0. It is pre- 



NITROGEN GROUP. 73 

pared by neutralizing dilute HX0 3 with (NH 4 )HO or a solu- 
tion of ammonium carbonate, and evaporating. It is used in 
the preparation of laughing gas. 

Exp. 123.— Prepare ' crystals of XH 4 C1, of (XH 4 )X0 3 , and of am- 
monium sulphate. 

Tests. 

XH 4 compounds, when heated with sodium or potassium 
hydrate, or slacked lime, give off NH 3 , known by its smell or 
by the fumes produced with HC1. Most NH 4 compounds are 
volatile at moderate temperatures. 

Exp. 124. — Heat a solution of XH 4 C1 with a solution of sodium hydrate 
in a test tube. To show by the HC1 test that XH 3 is" given off, hold a 
glass rod wet with HC1 in the tube. 

^Nitrogen 3Ionoxide (J$lO). 

X,0 (nitrous oxide, nitrogen protoxide, laughing gas), is a 
colorless, odorless gas, somewhat soluble in H 2 0. When pure 
it may be inhaled without danger. The effect of inhaling a 
small quantity is a kind of intoxication, that of a larger 
quantity, insensibility to pain. By pressure and cold it may 
be condensed to a colorless liquid, in which form it is sold as 
an anaesthetic. It is an active supporter of combustion, the 
burning of substances in it being almost as energetic as in O. 
N 2 is prepared by heating ammonium nitrate, (1STH 4 )N0 3 . 

To Prepare X 2 and Show Some of its Properties. — App. — The 
apparatus used in prepar- 
ing (Exp. 63). Mat.—3g. 
(XH 4 )X0 3 and pine splin- 
ter. Exp. 125. — Arrange 
to collect the gas over H 2 0. 
Put the (XH 4 )X0 3 in the 
tube, and heat. Fill the 
bottle with the gas. Exp. 
126. — To show the solu- 
bility of X 2 in H 2 0, mark 
the height of the H 2 in 

the bottle, and let the -n -, n t> VA 

' Fig. 19. — Preparation op X 2 0. 

bottle stand inverted in 

the trough for several hours. The H.,0 will rise above the mark. 

4 




74 NITRIC ACID. 

Exp. 127. — To show that N 2 supports combustion, cover the bottle, 
place it erect upon the table, and put one end of the splinter, burned to 
glowing, into it. 

Reaction.— (NH 4 )N0 3 = N 2 + 2 H 2 0. 

N Dioxide (N 2 2 or NO), N Tetr oxide 

(NO< or NO,). 

NO (nitric oxide) is a transparent, colorless gas, character- 
ized by its strong affinity for O, with which it forms N0 2 . It 
is best prepared from HN0 3 and copper (Cu). 

To Prepare NO and Show its Affinity for 0. — App. — The appa- 
ratus used in preparing N 2 0. Mat. — 2 or 3 g. Cu filings (or wire) and 
HN0 3 and H 2°- 

Exp. 128. — Arrange to collect the gas over H 2 0, put the Cu in the 
generator, add some H 2 and HN0 3 to it, and heat. Fill the bottle with 
the gas. Exp. 129. — Lift the bottle from the trough, and N0 2 fumes are 
formed from the combination of NO with of the air. 

N0 2 (nitrogen peroxide) is a brownish-red gas readily dis- 
solved by H 2 0. It is formed by the action of HN0 3 on met- 
als, etc. It is best prepared by the union of two volumes of 
NO with one rolume of O. 

NUric Acid (UNO*). 

Properties. 

HN0 3 (aqua fortis) is a fuming liquid, colorless when pure, 
but usually slightly colored from partial decomposition. Sp. 
gr. 1.52. It is highly corrosive, and is a powerful oxidizing 
agent. Its oxidizing action on organic matter often produces 
a deep yellow stain. It dissolves all the common metals but 
gold and platinum, and converts cotton, glycerine, and other 
organic products into highly explosive substances. Com- 
pounds formed by the action of HN0 3 on the metals, etc., 
are called nitrates. 

HXO3 AS A Solvent. — App. — 6 small test tubes and lamp. Mat. — . 
Small quantities of iron, copper, zinc, lead, mercury, and gold leaf, and 
HNO3 and H 2 0. 

Exp. 130. — Put the metals in the tubes, add to each a few drops of 
H 2 and a little HX0 3 , and heat. All but the gold dissolve. 



NITROGEN GROUP. 75 

Occurrence and Preparation. 

HX0 3 is not found free in nature. Its principal sources 
are potassium nitrate (K2s~0 3 , saltpetre), found in India and 
other tropical regions, and sodium nitrate (NajTO 3 , soda salt- 
petre), found abundantly in Peru and Nevada. It is pre- 
pared from one or the other of these nitrates (commercially.. 
from NaN T 3 ) and H 2 S0 4 . 

To Prepare HX0 3 . — App. — Distilling apparatus, etc. (p. 27) and 
mortar. Mat.— 10 g. KN0 3 or NaN0 3 and H 2 S0 4 . 

Exp. 131. — Powder the nitrate, put it in the retort, and add to it suf- 
ficient H 2 S0 4 to make a thin paste, then arrange the apparatus for dis- 
tilling, and heat. Continue heating until the reddish fumes, which 
appear at first and then disappear, are again formed. Preserve the 
HXO3 m a glass-stoppered" bottle, and allow the retort to cool. When 
the acid is prepared in large quantities, retorts of cast iron and receiv- 
ers of earthenware are used. 

React ion— KNO a -f H 2 S0 4 = KN"0 3 + HKS0 4 (hydrogen 
potassium sulphate). 

Exp. 132. — Prepare crystals of HKS0 4 by heating the residue, after 
the retort has become cold, with H 2 0, filtering and letting the filtrate 
stand. 

Uses and Tests. 
HN0 3 is much used in the chemical laboratory. It is used 
also in dyeing, in making nitro-glycerine, H 2 S0 4 , and the 
nitrates, also for etching on metals, and for many other pur- 



To Etch with HX0 3 . — App. — Piece of brass or iron and common pin. 
Mat, — Bees-wax and HN0 3 . 

Exp. 133. — Coat the metal or part of it with wax, with the pin write 
a name through the wax, and wet the writing with HN0 3 . After the 
acid has acted for a few minutes, clean the surface and the name will 
appear. Names may be written in acid, and hence etched, with a glass 
tube, one end of which is reduced to a point with a small opening. 

HNO3 is known by the red fumes produced when it acts on 
certain metals (Exp. 130), and by changing the colors of cer- 
tain organic substances to yellow. The nitrates deflagrate 
when heated on charcoal. 



76 AIR. 

Exp. 134. — Make the tests for HX0 3 above indicated, using a piece of 
copper wire, a piece of quill, and potassium nitrate. 

Air (O f W, etc.) 

Properties. 
Air is the invisible gas that surrounds us. When pure it is 
transparent, colorless, and odorless. It exerts a pressure of 
about 15 pounds to the square inch (at the level of the sea) on 
the earth's surface. The weight of 100 cubic inches is about 
31 grains. 

Composition of Air. 
Air is composed mainly of a mixture of O and N, the per- 
centage composition being : 

By Measure. By Weight. 

20.9 23.1 

N 79.1 76.9 

100.0 100.0 

It contains also a small quantity of C0 2 , a trace of ammo- 
nia, and a variable amount of H 2 vapor, sometimes in a 
gaseous form and sometimes in the form of clouds. The com- 
position of air may be approximately determined by consum- 
ing its O with phosphorus (P). 

To Analyze Air. — App. — Large test-tube, and strip of light card- 
board 2 in. long and \ in. wide. Mat. — Piece of P (see Caution, p. 47) 
twice as large as a grain of wheat, and H 2 in a saucer. 

Exp. 135. — Bend the cardboard into a U-shape, put the P in the bend, 
and slip the strip with the P into the test-tube inverted. Then support 
the tube with its mouth under H 2 0. Mark the height of the H 2 within 
the vessel, and let the apparatus stand 24 hours. The O combines with 
the P, forming P 2 3 (p. 80) which is absorbed by the H 2 G, and H 2 rises 
and occupies a volume of the vessel equal to that of the O. Measure 
the height of the H 2 ; this is about one-fourth of the height of the 
tube. 

To Show that Air Contains C0 2 . — App. — The blower (p. 136), glass 
tube 6 in. long, and piece of window glass. Mat. — Lime water in a 
beaker. 

To prepare lime water, stir well 15 or 20 g. of quicklime with half a 



NITROGEN GROUP. 77 

litre of H 2 and filter. The clear filtrate is lime H 2 0. When C0 2 comes 
in contact with this liquid, a white precipitate of calcium carbonate 
(CaC0 3 , chalk) is produced. 

Exp. 136. — Connect the glass tube with the blower as the blowpipe is 
connected with it, dip the tube in lime H 2 0, and start the H 2 in the 
blower. The air bubbles through the liquid, which becomes milkwhite. 
The precipitate is noticeable only after the passage of a large amount 
of air. Air may be forced through the lime H 2 with a pair of bellows, 
to the nozzle of which a rubber tube is attached. 

Exp. 137. — Pour a little lime H 2 on the glass, and in a few minutes 
a film of CaC0 3 will cover it. Let the liquid evaporate to dryness and 
there will be a spot of CaC0 3 on the glass. 

Permanence and Purity of the Air. 
The principal gases of the air are unchangeable except 
under very extraordinary conditions. O liquefies when sub- 
jected to a pressure of 320 atmospheres at — 140° C, and N 
under a pressure of 200 atmospheres at 13° C. The purity of 
the air is preserved by gaseous diffusion, all its gases mingling 
with one another to produce a uniform mixture. 

PHOSPHORUS (P) 31. 

Properties. 

P is a wax-like solid, colorless and almost transparent when 
freshly prepared, but becoming brownish and opaque, espe- 
cially when exposed to light. Sp. gr. 1.8. It is insoluble in 
H 2 0, somewhat soluble in petroleum and other oils, and very 
soluble in carbon disulphide (CS 2 ). It melts at 44° C. and 
kindles below the boiling point of H 2 0, burning with great 
energy ; the product of the combustion is P 2 5 . The extreme 
combustibility of P renders it necessary to keep it under H 2 
and handle it with great care. (See Caution, p. 47.) 

P combines slowly with O of the air at ordinary tempera- 
tures, P 2 3 being formed, and emits a faint light visible in the 
dark, called phosphorescence. Phosphorescence is illustrated by 
the glowing line of light seen when a match is struck on a wall 
in the dark. 

Solubility and Inflammability of P. — App. — Small test-tube, beaker, 



78 phosphorus. 

crucible, piece of filter paper, retort stand, and block of wood. Mat. — 
4 pieces of P, each about half as large as a grain of wheat, CS 2 and 
olive oil. 

Exp. 138. — Dissolve a piece of P in 2 or 3 c.c. of CS 2 , put the filter 
paper on a ring of the stand, and pour the solution on it. The evapo- 
ration of the liquid leaves on the paper a thin film of P which bursts 
into flame. 

Exp. 139. — Dissolve by heating gently a piece of P in 2 or 3 c.c. of 
olive oil, rub some of the solution on the hands or face, and go into a 
dark room. The surface rubbed is luminous. 

Exp. 140. — Boil some H 2 in the beaker, and put on it the crucible 
containing a piece of P. The P will ignite. 

Exp. 141. — Rub a piece of P on the block with the end of a lead 
pencil. It will ignite. 

Red phosphorus is an allotropic form of P. It is prepared 
by heating ordinary P for several hours at a temperature of 
about 240° C. in an atmosphere of some inert gas, as C0 2 . 
This treatment changes completely the properties of the sub- 
stance, for red P has a sp. gr. of 2.14, is insoluble in CS 2 and 
does not take fire at ordinary temperatures. At a temperature 
a little above 240° C. it changes into common P. 

Luminous paint is a mixture applied to surfaces to render them lumi- 
nous. The phosphorescent substance (the method of its manufacture 
is a secret), the chief ingredient of which is calcium sulphide, is mixed 
with suitable oils or varnishes, and these are applied as ordinary paints. 
Surfaces coated with the mixture, after being exposed to light, are suf- 
ficiently luminous to render objects about them visible. Luminous 
paint will doubtless come into extensive use for coating clock and watch 
dials, buoys, divers' suits, etc. The mixture may also be combined with 
such substances as celluloid, papier mache, etc., to render articles made 
of these substances luminous. 

Occurrence and Preparation. 

P abounds in nature as a constituent of calcium phosphate 
(the chief earthy constituent of bone), and of various other 
compounds. There are about If pounds of P in the body of 
an adult person. 

P is prepared from various mineral calcium phosphates. 
The phosphate is first completely decomposed with H 2 S0 4 , 



NITROGEN GROUP. 79 

calcium sulphate (CaS0 4 ) and phosphorus pentoxide (P 2 5 ) 
being formed. The CaS0 4 is filtered off'. The filtrate con- 
taining the P 2 5 is then condensed by evaporation and mixed 
with coarse wood charcoal ; the mixture is dried, and finally 
strongly heated in retorts, w T hen the P distills over and is con- 
densed in H 2 0. It is cast in moulds for market. 

Uses and Test. 
P is used chiefly in making friction matches. The wood 
for matches is cut into splints by machinery, the splints are 
dipped into melted S, parafnne, or stearine, and tipped with a 
composition consisting of P, a substance (generally saltpetre, 
manganese dioxide, or potassium chlorate) which readily gives 
up O, and glue or gum. Safety matches are tipped with a 
mixture of potassium chlorate and antimony sulphide ; the 
composition contains no P. These matches are rubbed in 
lighting on a prepared surface composed of red P, manganese 
dioxide, and glue. Free P is detected by its faint luminosity. 

Hydrogen Phosphide (IPH % ). 

PH 3 (phosphuretted hydrogen) is a colorless, offensive 
smelling gas, which possesses the property, under certain con- 
ditions, of inflaming spontaneously on coming in contact with 
air. It is produced naturally by the decay of animal matter. 
It is generally prepared by heating P with a strong solution 
of a caustic alkali, H 2 being decomposed. 

To Prepare PH 3 . — App. — Short-necked flask of about 200 c.c. capac- 
ity, with a long glass delivery tube, retort stand with wire gauze, and 
lamp. Mat. — 40 g. of potassium or sodium hydrate ("Concentrated 
lye" used in making soap answers the purpose) dissolved in about 100 
c.c. of H 2 0, about 1 g. of P in several fragments, ether, and H 2 in 
water pan. 

Exp. 142. — Support the flask on a ring of the stand and adjust the 
delivery tube so that its free end dips just below the surface of the H 2 
in the pan ; then put in the alkali solution, P, and a few drops of ether 
(the vapor of which expels the air from the flask), and heat. PH 3 
forms (after heating for several minutes) and its bubbles, on coming 
into the air, burst into flame, forming, in still air, beautiful rings of 
smoke. 



80 ARSENIC. 

Phosphorus Oxides and Acids. 

Phosphorus trioxide (P 2 3 , phosphorus anhydride) is a white, 
amorphous powder formed by the burning of P in a limited 
supply of air. Phosphorus pentoxide (P 2 5 , phosphoric anhy- 
dride) is a white, flocculent powder, with a strong affinity for 
H 2 0. It is formed by the rapid burning of P in an excess 
of air or O. 

To Prepare P 2 5 . — App. — Wide-mouthed 1. bottle, saucer (or plate), 
and small porcelain crucible. Mat. — \ g. P. 

Exp. 143. — Dry the app. thoroughly, which may be done by leaving 
it supported for 15 or 20 minutes over a kerosene flame, then put the P 
in the crucible placed on the saucer, light it, and invert the bottle over 
it. The P 2 5 collects on the sides of the bottle and in the dish. Exp. 
144._To show the affinity of P 2 5 for H 2 0, throw a little of it on H 2 0. 
A hissing sound, like that produced by hot iron in II 2 0, is heard. 

There are several acids of P, three of which are formed by 
the union of P 2 5 with H 2 ; ordinary phosphoric acid 
(H 3 P0 4 ) pyro-phosphoric acid (H 4 P 2 7 ) and meta-phosphoric 
acid (HP0 3 ). 

ARSENIC (As) 75. 

As is a steel-gray, brittle solid, with a metallic lustre and a 
crystalline structure. Heated to dull redness, it emits a garlic- 
like odor by which it is known. It forms with many metals 
alloys which it tends to render bright and brittle. Shot con- 
tains a little As, which is added to the melted lead to help it 
form into regular globules. As is very poisonous ; it is the 
chief constituent of "fly poison." 

As in small quantities, sometimes free, is widely distributed. 
Its most abundant compound is an ore composed of iron, S, 
and As. It is generally prepared from this ore. 

Hydrogen Arsenide (AsHJ. 
AsH 3 (arseniu retted hydrogen) is a colorless, offensive 
smelling, and intensely poisonous gas. It may be prepared 
mixed with H by putting a solution of As or of an As com- 
pound into a vessel in which H is generating from zinc (Zn) 
and dilute acid. 



NITROGEN GROUP. 81 

To Prepare AsH 3 . — Marsh's Test. — App. — Large test-tube with cork 
and jet-tube like that for burning H (Exp. 20), and the lid of a porce- 
lain crucible (or a piece of a saucer or plate). Mat. — 2 or 3 g. Zn, 
HC1, and an aqueous solution of white arsenic. 

Exp. 145. — Generate H in the tube, light the jet when the air is ex- 
pelled from the app., and hold the lid in the flame. No dark spots 
appear if the materials contain no As. Add a few drops of the As so- 
lution and relight the jet. Hold the lid again in the flame, which is 
now of a whitish color, and As is deposited on it, forming a black 
metallic spot. The forming of As spots in this way is 31arstis Test. 
By it exceedingly small quantities of As can be detected. Repeat the 
test, using a small piece of green wall or box paper, or scrapings of 
green paint instead of the As solution. 

Arsenic THoxide (As 2 O s ). 

As 2 3 (arsenious oxide, acid or anhydride, white arsenic, 
arsenic) is a white solid usually in the form of a compact 
cake. It is only sparingly soluble in II 2 0, but dissolves 
readily in hot HC1. When heated it volatilizes unchanged ; 
if heated with carbon, it gives up its O, and metallic As is 
produced. It is intensely poisonous. Its best antidote is 
freshly precipitated ferric hydrate. 

To Volatilize and Crystallize As 2 3 . — App. — Piece of glass tubing 
3 or 4 in. long, and lamp. Mat. — Piece of As 2 3 as large as a pin's 
head. 

Exp. 146. — Volatilize the As 2 3 in the tube, first warming the tube 
beyond the As 2 3 . The substance crystallizes on cooling. Examine 
the crystals with a lens. 

To Produce As by Heating As 2 3 with Charcoal. — Reduction test. — 

App. — Piece of glass tubing 3 

or 4 in. long, drawn at one end 

and sealed as shown in Fig 

on , , , , . , r x Fig. 20. — Reduction of As„Oo by 

20, lamp, and blow-pipe. Mat. n - 3 

UHARCOAL. 

Piece of As 2 3 as large as a 

pin's head, and fragment of charcoal. 

Exp. 147. — Put the As 2 3 in the bottom of the tube, and the C just 

above it. Heat the C red-hot with a blow-pipe flame, then throw the 

flame on the As 2 3 . The As forms a metallic mirror on a cold part of 

the tube. This experiment illustrates a delicate method of detecting As. 

As 2 3 is obtained chiefly from Germany in the roasting of 

4* 



82 BISMUTH. 

arsenical nickel ores. The As of the ore combines with O 
from the air. It is used in making Paris green, opaque glass, 
in dyeing and calico printing, as a medicine, and for other 
purposes. 

Arsenic sulphides are realgar (As 2 S 2 ), a red solid found as a 
natural product, and orpiment (As 2 S 3 ), a yellow solid found as 
a natural product and also precipitated by hydrogen sulphide 
from arsenical solutions. The former is used in making fire- 
works, and the latter as a paint. 

ANTIMONY (Sb) 120. 

Sb is a bluish-white brittle solid, with a metallic lustre and 
a plated crystalline structure. At red heat it burns, antimony 
trioxide (Sb 2 3 ) being formed. It is a constituent of several 
useful alloys, as type-metal (Sb and lead) which it causes to 
expand on solidifying and completely fill the mould, and 
Britannia metal, pewter, etc., to which it contributes hardness. 

Sb is often found alloyed with As, silver, and other metals. 
It also occurs in combination with S in the sulphides of other 
metals. Commercial Sb is obtained from the mineral stibnite 
(Sb 2 S 3 ). 

Burning of Sb. — App. — Blow-pipe, piece of charcoal containing a 
cavity and mortar. Mat. — Sb. 

Exp. 148. — Powder a little Sb, put it into the cavity of the coal, and 
direct the blow-pipe flame downward upon it. It soon melts, forming a 
bright globule. Drop this on the table or floor, and it will break into 
numerous smaller globules, which scatter in all directions, marking 
their paths by a smoky ash formed by the burning of the metal. 

BISMUTH (Bi) 210. 
Bi is a grayish-white, hard, brittle metal which, when pure, 
crystallizes more readily than any other metal. It combines 
to form alloys which are remarkable for their easy fusibility. 
An alloy composed of 2 parts of Bi, 1 of lead, and 1 of tin, 
called " fusible metal," melts at about 94° C. Bi is usually 
found in the metallic state, but it sometimes occurs in combi- 
nation with other metals, especially S. 



GOLD GROUP 83 

The other elements of the N group are rare. Vanadium 
possesses the property of attacking vessels of glass and porce- 
lain in which it is heated. The yellow oxide of Uranium is 
used for coloring glass, and the black oxide as a pigment for 
painting on porcelain. These elements occur chiefly in rare 
minerals. Uranium is always found in nature combined 
with O. 

GOLD GEOUP. 

GOLD, BORON, THALLIUM. 

GOLD (An) 197. 

Au is the only metal having a yellow color. It is very 
dense and almost as soft as lead. Sp. gr. 19.3. It is ex- 
tremely ductile and the most malleable of the metals, the 
thinnest gold leaf being only T o^oo °f a millimetre thick. It 
does not change in air at temperatures below its melting point, 
and is not soluble in any single acid. Its common solvent is 
aqua regia (p. 43). It is always alloyed for use, generally 
with copper or silver, as in the pure state it would be too soft. 
Au for jewelry, watches, and coins is alloyed with, copper ; our 
gold coins consist of 9 parts Au to 1 of copper.* 

Exp. 149. — Find the sp. gr. of a gold ring, also of a gold coin. 

Au is widely distributed in nature, but generally in very 
small quantities. The most valuable deposits are found in 
California, Colorado, Nevada, and Australia. It usually oc- 
curs in the metallic state, alloyed with silver. It is found 
most frequently in quartz rock, and in alluvial soil known as 
placers. Large lumps are sometimes found ; a nugget from 
Australia weighed 184 lbs. 

* Seven metals were known to the ancients; gold, silver, copper, tin, 
iron, lead, and mercury. Gold, occurring as it frequently does in the 
sands of rivers, was probably the first metal known to man. Repre- 
sentations of the washing and fusing of gold are found as early as 
2500 B. C. on Egyptian tombs. The oldest coins in existence are the 
electrum staters of Lydia, which consist of 3 parts gold to 1 of silver. 
On account of its unchangeableness, gold was called by the ancients 
the king of metals. 



84 



BORON. 



Aii in quartz is extracted by bringing the crashed ore in 
contact with mercury, with which the Au forms an amalgam, 
and then removing the mercury by distillation. Au in placers 
is collected by a process of washing by which the lighter 
portions of the deposits are carried off by the H.,0. The 
grains of the metal are separated by mechanical means and 
the finer portions by the amalgamation process. Hydraulic 
mining consists in washing down with H,0 under great pres- 




L. — Hydraulic Mining 



sure, immense beds of auriferous deposits into channels so 
constructed as to collect the heavier sediment containing the 
Au. 

There are several compounds of gold, the most familiar of 
which is auric chloride (AuCl 3 ), formed by dissolving Au in 
aqua regia. 

BORON (B) 11. 

B has three allotropic forms. Crystallized B is almost as 
hard as diamond, and the crystals are very brilliant. B is al- 
ways found in nature combined with O as a constituent of 
boric acid and the borates, the most important of which is 
borax. 

Boric or Boracic Acid (H z BOJ. 

H 3 B0 3 is a white, greasy-feeling, crystalline substance, 
readily soluble in warm ELO and alcohol. The alcoholic 
solution burns with a green flame which is a test for the pres- 



IRON GROUP. 85 

ence of B. H 3 B0 3 is collected in large quantities from the 
hot vapors issuing from the soil in certain volcanic districts 
of Tuscany. It may be obtained from any borate by the ad- 
dition of an acid. 

To Obtain H 3 B0 3 from Borax (Xa 2 B 4 7 ). — App. — 2 test-tubes, lamp, 
and app. for filtering. Mat. — 2 g. borax, H 2 0, and HC1. 

Exp. 150. — Put the borax and about 10 c.c. of H 2 in one of the 
tubes, and heat until the borax dissolves. Filter, if the liquid is not 
clear, and add some HC1. Crystals of H 3 B0 3 separate as the liquid 
cools. The HC1 combines -with the Na of the compound, forming XaCl 
and liberating the H 3 B0 3 . 

Exp. 151. — Make the flame test for H 3 B0 3 by shaking a little of the 
acid with alcohol, pouring the solution on a tin lid, or in a crucible, and 
lighting it. The flame is tinged green. 

Thallium is a rare metal resembling lead. Its compounds 
resemble those of both potassium and silver ; they color a 
flame green. Tl is found in some varieties of iron pyrites, 
and in certain mineral waters. 

IEOE" GEOUP. 

IRON, MAXGAXESE, XICKEL, AXD COBALT. 

IRON (Fe) 56. 

Properties axd Varieties. 
Pure Fe is a white, soft, very malleable, ductile metal. 
Ordinary Fe, which contains small quantities of carbon, sili- 
con, sulphur, and phosphorus, has a grayish-white color, and 
is harder than the pure metal. Fe dissolves in dilute HC1 
and H 2 S0 4 , and forms two series of salts ; ferrous, in which it 
acts as a dyad, and ferric, in which it acts as a hexad. It re- 
mains unchanged in dry air at ordinary temperatures, but 
rapidly oxidizes in moist air.* 

*lron was known at a very early date. According to the book of 
Genesis its discovery is attributed to Tubal Cain ; pagan tradition as- 
signs the discovery to Vulcan. The Lacedaemonians coined iron into 
money, and it was used in Homer's time for axes and other instruments. 
Aristotle (born B. C. 384) describes the manner in which the Chalybes 
produced iron, and also a process of making cast steel. 



86 



IRON. 



There are two varieties of Fe, east iron and wrought iron, 
differing mainly by reason of the different amounts of carbon 
they contain. Cast iron contains from 2 to 6 per cent., and 
wrought iron less than § per cent. 

Cast iron has a crystalline or granular structure, is hard 
and brittle. It has the property of expanding in cooling, and 
hence will exactly copy a mold. It differs greatly in quality, 
the hardest variety, which is white and crystalline, being 
known as white iron, and the softest, which is gray and gran- 
ular, as gray iron. 

Wrought iron has a fibrous structure, is soft, malleable, and 
very tenacious. It is prepared from cast iron by burning out 
carbon, silicon, and other substances. This is effected by a 
process called puddling in a reverberatory furnace, a furnace 




Fig. 22. — Puddling Furnace. 

so constructed that the substance is heated by the flame re- 
flected upon it by the curved roof. The melted metal is con- 
stantly stirred to bring it in contact with air. 

Occurrence and Preparation. 

The free occurrence of Fe in nature, except in aerolites, is 
doubted, but its ores are very numerous and abundant, and it 
is a constituent of almost all natural substances. Its most 
valuable ores are the oxides and carbonates. 

In extracting Fe from its common ores (oxides), H 2 0, C0 2 , 
etc., are first expelled from the ore by roasting ; the O is re- 
moved by igniting with C, C0 2 being formed ; and finally the 
earthy impurities are removed by the fusion of these with a 
flux which has been mixed with the ore, slag being formed. 

The redaction is made in a tall furnace lined with fire-brick, 



IRON GROUP. 



87 



called a blastfurnace. The furnace is open at the top and 
closed at the bottom, near which pipes enter to convey hot air, 




Fig. 23. — Blast Furxace. 

which is forced in to support the combustion. The furnace is 
charged at the top, the fuel (charcoal, anthracite coal, or coke), 
the ore, and the flux (generally limestone), being placed in 
alternate layers. The melted Fe and slag flow out at the bot- 
tom into a dam ; the slag flows off over the top, and the Fe is 
drawn off into channels made in sand. This product is east 
iron. 

The great variety of uses to which iron can be put, and 



83 COMPOUNDS OF IRON. 

hence its close connection with the world's work, renders it 
the most useful of all metals. 

Oxides of Iron. 

Ferrous oxide (FeO) is a black powder about which little is 
known on account of its proneness to absorb O and form ferric 
oxide. Ferric oxide (Fe 2 3 , iron sesquioxide) is widely dis- 
tributed as hematite and specular iron ore. It is also prepared 
for paint. Rouge is a fine variety used for polishing jewelry, 
glass, etc. Magnetite (Fe 3 4 ) occurs as an ore, and is the 
richest of the iron ores. 

Hydrates of Iron. 

Ferrous hydrate (FeH 2 2 ) is a white, unstable powder. It 
may be precipitated by the addition of (NH 4 )HO to a solu- 
tion of ferrous sulphate. 

Ferric hydrate (Fe 2 H 6 6 ), is a red powder, which may be 
produced by the addition of (NH 4 )HO to a solution of ferrous 
sulphate to which a few drops of HN0 3 have been added. It 
is valuable as an antidote for arsenic. Yellow ochre is a native 
ferric hydrate used as a paint. Iron rust is mainly ferric 
hydrate. The black stain formed around the heads of nails 
in unseasoned oak, is iron tannate, formed by the combination 
of tannic acid of the wood with the metal or its carbonate. 

Sulphides of Iron. 

Ferrous sulphide (FeS, protosulphide), is a dark, brittle sub- 
stance, prepared by fusing Fe with S. It is used in preparing 
hydrogen sulphide. Ferric disulphide (FeS 2 , iron pyrites) is 
an abundant ore occurring in cubical crystals. It is value- 
less for its iron, but is used as a source of S and in the manu- 
facture of H 2 SO. 

Sulphates of Iron. 

Ferrous sulphate (FeS0 4 ) is prepared by roasting Fe 2 S gen- 
tly, also by dissolving Fe or FeS in dilute H 2 S0 4 . Its solu- 
tion produces crystals called green vitriol or copperas (FeS0 4 



IRON GROUP. 89 

-f 7 H 2 0). These slowly effloresce in dry air, becoming cov- 
ered Avith a white crust. Green vitriol is used extensively in 
dyeing and in making Prussian blue. 

Dyeing with Green Vitriol. — Mat. — Piece of cotton cloth, solution 
of green vitriol, and solution of nut galls, prepared by boiling in a 
flask 5 g. of the powdered galls in 100 c.c. of H 2 for several hours, 
and filtering. 

Exp. 152. — Dip the cloth into the galls solution, and when dry, dip it 
into the vitriol solution. It will be dyed black with the iron tannate 
formed. 

Exp. 153. — Find the sp. gr. of Fe. Exp. 154. — Prepare FeH 2 2 , 
Fe 2 H 6 6 and FeS0 4 -|-^ H 2 0. Notice how the precipitate of the first 
changes in standing, first to green and then to a reddish brown. 

Steel. 

Steel is a metal of great strength, intermediate between cast 
and wrought iron. It contains from .2 to 2 per cent, of car- 
bon. It embraces several varieties, known as Siemens steel, 
crucible steel, blister steel, etc., according to the method of 
manufacture. The most valuable property of steel for cutting 
instruments, springs, etc., is that which enables the metal to 
vary its hardness. Heated to redness and plunged into cold 
H 2 0, it becomes so hard that it will scratch glass ; reheated 
to redness aud cooled slowly, it acquires almost the softness of 
ordinary iron ; and between these extremes any degree of 
hardness can be obtained. Tempering consists in reheating 
the hardened steel to a temperature below redness and gradu- 
ally cooling it. 

Steel is generally produced either by carbonizing wrought 
iron, called the cementation process, by decarbonizing cast 
iron, called the Bessemer process, or by melting scrap iron in 
a bath of cast iron by a gas flame, called the Siemens-Martin 
or open-hearth process. 

By the cementation process, bars of wrought iron are con- 
verted into steel by imbedding them in charcoal in close boxes 
and heating them to redness for several days. The iron grad- 
ually takes up C. 

By the Bessemer process, melted cast iron is poured into a 




90 NICKEL, COBALT. 

large covered crucible called a converter, which swings on 
pivots to render it easily emptied. A strong blast of com- 
pressed air is forced into the molten mass 
through holes in the bottom of the crucible, 
oxidizing the C and silicon and some Fe. 
This oxidation produces intense heat which 
keeps the iron melted. After the action has 
continued for several minutes, the air-current 
is stopped and a small quantity of spiegeleisen 
(a variety of pig iron containing manganese 
Fig. 24.— Besse- and C) is added, by means of which the 
mer Converter. j ron j g recar b nized or converted into steel. 
The melted metal is run into ingots. 

By the Siemens-Martin process, the scrap and cast iron are 
heated in a reverberatory furnace by a burning mixture of 
hydro-carbon gases and air, and the melted product is recar- 
bonized by the addition of spiegeleisen, as in the Bessemer 
process. 

MANGANESE (Mn) 55. 
Mn is a grayish-white hard metal, which rapidly oxidizes in 
moist air. It does not occur free in nature. Its most com- 
mon and valuable ore is the dioxide. 

Compounds, 

Manganese dioxide (Mn0 2 , black oxide of manganese) is used 
extensively as a source of O and CI, and for coloring glass. 
Potassium permanganate (K 2 Mn 2 8 ) is a dark purple, crystal- 
line salt. It readily gives up its O, and for this reason is used 
extensively as a disinfectant. 

NICKEL (Ni), COBALT (Co). 

Ni and Co are white metals very much alike. Ores of Ni 
occur in Lancaster County, Pa. (where the largest deposit 
known in the U. S. is found), New Caledonia, and other places. 
Co is found associated with Ni. Ni is an ingredient of Ger- 
man silver, and is much used for coating (nickel plating) iron 



CHROMIUM GROUP. 91 

and steel. Cobalt monoxide (cobaltous oxide) is used to give a 
blue color to glass. A dilute solution of cobaltous chloride 
forms blue sympathetic ink. 

Exp. 155. — Write on paper with an H 2 solution of cobaltous chlo- 
ride so dilute that the characters cannot be seen, and warm the paper. 
The writing becomes blue. Breathe on the paper and the blue disap- 
pears. The color is due to the removal of H 2 from the chloride. 

CHROMIUM GROUP. 

CHROMIUM, MOLYBDENUM, TUNGSTEN. 

CHROMIUM (Cr) 52.2. 

Cr is a white metal, somewhat rare, and is not found free 
in nature. Its principal ore is chrome iron (FeCr 2 4 ). The 
chromium compounds, many of which have bright colors, are 
used as paints, in dyeing, etc. 

To Prepare Chrome Alum. — App. — Small beaker, and evaporator. 
Mat. — 5 g. potassium dichromate (K 2 O 2 7 ), and H 2 0, H 2 S0 4 , and alcohol. 

Exp. 15G. — Dissolve by heating the K 2 Cr 2 7 in 30 c.c. of hot H 2 0, and 
when the liquid is cool, add 5 c.c. of H 2 S0 4 ; when the liquid is again 
cool add 3 c.c. of alcohol. Let the beaker stand for several hours, and 
its bottom will become covered with crystals of chrome alum. Potas- 
sium sulphate and chromium sulphate, which are formed, combine to 
form the alum. The alcohol becomes oxidized. 

The other elements of the Cr group are rare. Molybdenum 
closely resembles graphite. It is remarkable for its numerous 
and very complex compounds. Tungsten, when alloyed with 
steel, renders that metal very hard. Sodium tungstate has 
been used to lessen the inflammability of dress goods, etc. 
These elements occur only in a few minerals. Mo is usually 
found in combination with S, and Wo with calcium. 

PLATINUM GROUP. 

PLATINUM, IRIDIUM, OSMIUM, PALLADIUM, RHODIUM, RUTHENIUM. 

PLATINUM (Pt) 194.8. 
Pt is a grayish-white, very heavy metal. Sp. gr. 21.5. It 



92 DIAMOND. 

is exceedingly malleable, and so ductile that it may be drawn 
into wire only T oVo of a millimetre in diameter. It does not 
change in air, and is infusible at the temperature of the hot- 
test blast furnace, but its alloys with zinc, lead, tin, silver, and 
other metals are easily fusible. It is not soluble in any single 
acid, but dissolves slowly in aqua regia. Platinum black and 
platinum sponge are preparations of the metal in a finely 
divided state. 

Pt is found in the metallic state, and is generally alloyed 
with the other elements of its group, with copper, silver, etc. 
Its chief locality is the Ural mountains, but it is found also 
in California and other places. Pt is of great use to the 
chemist for crucibles and other apparatus, and is also used for 
the stills and siphons employed in the manufacture of H 2 S0 4 . 

The other elements of the Pt group are much like Pt in 
color and hardness, and are all difficult to fuse. Iridium is 
the hardest known metal ; most of its compounds are coloring 
agents. Osmium has never been fused. The most remarkable • 
property of Palladium is its power to absorb or "occlude" H. 
In a finely-divided condition, it will absorb nearly 1000 times 
its volume of this gas. The sp. gr. of Ir is 21.15, and of Os 
21.4. These elements are found in " platinum ores." 

CAEBOTsT GKOUP. 

CARBON, SILICON, TIN, TITANIUM, ZIRCONIUM. 

CARBON (C) 12. 
C has three allotropic foruis, diamond, graphite, and amor- 
phous carbon. 

Diamond. 

Diamond is a (generally) colorless, brittle, crystalline solid, 
and the hardest known substance. Its great brilliancy is due 
to its power of dispersing and refracting light, and to its 
lustre. It resists the action of all known chemicals, and re- 



CARBON GROUP, 93 

mains unchanged by heat unless made red hot and put into O, 
when it burns with a brilliant light.* 

The diamond is found in various places, the most extensive 
field being that of South Africa. It occurs as a semi-trans- 
parent pebble encased in a brownish crust. Its origin is un- 
known. Small diamonds have been produced artificially. 
The diamond is usefully employed in cutting glass, pointing 
drills for boring hard rocks, and for the jewels of watches. 

Graphite. 

Graphite (plumbago, black lead) is a dark, friable substance 
with a metallic lustre, and is either crystalline or amorphous. 
Like diamond, it does not fuse when subjected to the strongest 
heat, and burns in O. It generally contains some iron, but 
contains no lead. 

Graphite is somewhat rare. Large deposits of it are found 
in Cumberland, Eng., at St. John, N. B., and in Siberia. It 
is probably of vegetable origin. Its principal use is for lead 
pencils (so called because the mark which they make on paper 
is similar to that made by lead). It is also used for crucibles 
in which to melt refractory substances, as gold and silver, for 
stove polish, and for diminishing the friction of machinery. 

Amorphous Carbon. 

Amorphous carbon includes charcoal, animal charcoal, lamp- 
black, etc., and mineral coal. 

Charcoal. — Charcoal is a black, brittle, amorphous, very 
porous solid. It has the property, due mainly to its porosity, 

* The diamond was first known to the Assyrians. It was first worn 
in the rough state and was thought to possess various medicinal virtues. 
The process of diamond cutting was discovered in 1476. The diamond 
was long regarded as a variety of silica, and its constitution was not 
correctly determined until the end of the 17th century. Two of the 
most celebrated diamonds in the world are the Koh-i-noor (mountain of 
light), weighing 123 carats and valued at about $10,000,000, belonging 
to Queen Victoria, and the Orloff, weighing 195 carats, belonging to the 
Russian crown. The largest diamond found in the U. S. was picked up 
near Richmond, Ya., in 1856. Its weight was 23.7 carats. Diamonds 
that are colorless and perfectly transparent resemble a drop of clear 
water and are called diamonds of the ''first water." 



94 CHARCOAL. 

of absorbing gases in large quantities, of destroying odors, 
and of removing colors. It is insoluble in all liquids and only 
slightly fusible even in the intense heat of the voltaic arch. 
It Combines with O with great energy at high temperatures, 
but at ordinary temperatures is one of the most unchangeable 

of substances. 

Porosity of Charcoal.— App.— Lamp, blow-pipe, light iron wire, and 
piece of lead. Mat.— 2 pieces of C, one of which is quite small, cold 
H.,0, and warm H 2 0. 

'Exp. 157.— Heat the small piece of C, held by means of the wire, to 

redness, and continue heating for several minutes, then plunge it into 

the cold H 2 0. It will sink because air has been expelled from its pores. 

Exp. 158. — Attach the lead to the other piece of C and sink the C in 

the warm H 2 0. Air will be driven from it and escape through the H 2 0. 

Odor-Destroying Property of Charcoal.— App.— Test-tube. Mat. 

2 g. ferrous sulphide (FeS), 2 or 3 g. powdered C, and HC1. 

Exp. 159. — Put the FeS in the tube and cover it with dilute HC1. 
H 2 S, known by its smell, is produced. Put C in the tube, and the odor 
will disappear. 

Color-Destroying Property of Charcoal. — App. — Crucible, 2 fun- 
nels, etc, for filtering, retort stand, and lamp. Mat.— A small amount 
of the blue compound of iodine and starch (Exp. 61), a solution of blue 
litmus in H 2 and 5 g. bone ash (p. 95). 

Exp. 160. — Heat the ash strongly in the crucible, then put it into the 
blue liquids, shake them well, and filter. Their colors will be destroyed. 
If the liquids do not come through colorless, pass them through again. 
Combining of Charcoal with O.—App.— Piece of glass tubing 3 or 4 
in. long, sealed at one end, piece of C with a cavity, lamp, and blow-pipe. 
Mat.— I g. copper monoxide (CuO), T V g. powdered C and £ g. litharge 
(PbO). 

Exp. 161.— Mix the CuO and C and heat the mixture strongly in 
the tube. The C combines with the of the CuO, forming C0 2 , which 
escapes, and copper, known by its yellow color, remains. 

Exp. 162. — Heat the PbO on the charcoal with a blow-pipe flame, and 
in a short time a globule of Pb will form. Explain. 

Charcoal is generally prepared by burning large piles of 
wood, from which air is partly excluded by a covering consist- 
ing of moist earth, leaves, etc. The liquid and gaseous in- 
gredients of the wood are thus expelled, and the solid portion 
remains. In countries where wood is scarce, charcoal is pre- 



CARBON GROUP. 95 

pared by heating the wood (also sawdust) in iron retorts ; the 
volatile products are collected. 




Fig. 25. — Preparation of Charcoal. 

To Show the Preparation op Charcoal. — App. — Narrow glass tube 
sealed at one end, lamp, and pincettes. Mat. — Piece of match with the 
friction end removed. 

Exp. 163. — Put the wood in the tube and, holding the tube with the 
opening inclined downward, heat it strongly until all the volatile pro- 
ducts are expelled. The wood will be converted into charcoal. Ee- 
move the coal when the tube becomes cold, if necessary by breaking the 
tube, and hold it in an alcohol flame. It burns without smoke. 

Charcoal is used as fuel in various metallurgical operations, 
and for reducing metals from their oxides in the smelting fur- 
nace. It is also used as a disinfectant. The lower ends of 
fence posts are sometimes charred to render them more durable. 

Animal charcoal (bone black, or bone ash) is prepared by 
heating bones in iron retorts. It is used extensively in sugar 
refining and as an ingredient of snoe-blacking. 

Lamp black is prepared by heating resin, pine knots, etc., 
and burning the disengaged vapors in a current of air not 
sufficient for their complete combustion. The familiar smoke 
on a lamp-chimney is lamp-black. The chief use of lamp- 
black is for black paint and printer's ink. 

Coke is a porous solid obtained as a residue in the distillation 
of bituminous coal. It is a secondary product of the manu- 
facture of illuminating gas. It is used extensively in the 
smelting of iron, for which it is prepared in large quantities. 



96 CARBON MONOXIDE. 

Gas carbon is a very hard substance formed on the inner 
walls of the retorts in the manufacture of illuminating gas. 
It is used as an ingredient in carbon battery plates and carbon 
rods of electric lamps. 

Mineral coal was formed by the slow decay of vegetable 
matter — moss, leaves, trunks of trees, etc. — without air and 
subjected to heat, moisture, and great pressure. Anthracite 
coal differs from bituminous in containing little of the H, O, 
and N of the original vegetable matter, having been subjected 
to a natural distillation. 

Coal Gas (C, H, etc.) 

Coal gas is a mixture of marsh gas (CH 4 ), olefiant gas 
(C 2 H 4 ), H, and other gases. It is prepared by heating bitu- 
minous coal in large iron retorts, the gas being driven off with 
various other gaseous and liquid products. Coke remains in 
the retort. 

The pipe conveying the expelled products from the retort 
dips into H 2 0, which condenses aqueous vapor, tar, and salts 
of ammonium. The gas is then cooled and separated from 
the remaining tar, etc., by passing through iron pipes called 
Condensers. Jt next passes through a tower filled with coke, 
over which H 2 trickles, to remove the remaining salts of 
ammonium, then over slacked lime to remove the hydrogen 
sulphide and C0 2 , and finally enters the gas holder, from 
which it is forced to the burners. One pound of good coal 
yields about 5 cubic feet of the gas. 

There are many organic substances composed of C and H, some of 
which will be treated under Organic Chemistry. 

Carbon Monoxide (CO). 
CO (carbonic oxide) is a colorless, odorless, poisonous gas. 
It burns with a blue flame, C0 2 being produced. In contact 
with heated metallic oxides it acts as a powerful reducing 
agent, combining with O with great energy. CO is a product 
of the combustion of anthracite coal, its burning producing 



CARBON GROUP. 97 

the blue flame often seen in coal stoves. It may be prepared 
by heating oxalic acid (H 2 C 2 4 ) with H 2 S0 4 . 

To Prepare CO. — App. — The apparatus used in preparing (Exp. 
63). Mat. — 1 g. H 2 C 2 4 and H 2 S0 4 and beaker of H 2 0. 

Exp. 164. — Arrange to collect the gas over H 2 0, put the H 2 C 2 4 and 
sufficient H 2 S0 4 to moisten it in the generator, and heat. Fill the re- 
ceiver with the gas. Exp. 165. — To show the burning of the gas, cover 
the receiver and put it erect on the table. Then light the gas and 
quickly pour H 2 into the receiver to force the gas out. 

Carbon Dioxide (CG 2 )» 

Properties. 
C0 2 (carbonic acid) is a colorless, slightly acid gas, 1.53 
times as heavy as air. It is so heavy that it can be poured 
like H 2 0. H 2 dissolves nearly its own volume of C0 2 at 
ordinary temperatures and pressures, and more than its volume 
when the gas is subjected to increased pressure and a lower 
temperature. H 2 0, containing CO, under pressure, effervesces 
when the pressure is removed. C0 2 does not burn, extin- 
guishes flame, and destroys life by suffocation. 

Occurrence and Preparation. 

C0 2 occurs uncombined in air. It is so heavy that it some- 
times collects in wells and caves, rendering them dangerous to 
enter. It may be tested for in such places with a lighted 
candle, which it puts out, and may be removed by introducing 
dry slacked lime or freshly burned charcoal, which absorbs it. 
C0 2 is a constituent of all carbonates, forming nearly one- 
half of limestone, marble, etc., from which it can be removed 
by heat, as in " burning lime." It is one of the chief products 
of combustion, respiration, fermentation, and the decay of or- 
ganic matter. 

C0 2 a Product op Combustion. — App. — Candle or kerosene lamp and 
large test-tube. Mat. — Lime water (p. 16). 

Exp. 166. — Hold the test-tube inverted for a few seconds over the 
flame, then remove it, covering it closely with a piece of wet paper, and, 
when sufficiently cool, pour in a little lime H 2 0. Shake the tube 
5 



CARBON DIOXIDE. 




keeping it covered, and the liquid becomes milky white on account of 

the precipitate of calcium carbonate formed. 

Fig. 26 represents an apparatus by which 
the result of Exp. 166 may be more beauti- 
fully shown. The tube t extends nearly to 
the bottom of the bottle 6, and the tube e 
just through the cork. To use the appa- 
ratus, lime H 2 is put into the bottle, the 
lamp lighted, the free end of e connected 
with the upper bottle of the blower (p. 136) 
and the H 2 of the blower started. The 
products of the combustion are drawn 
through the lime H„0. The operation may 
be performed slowly by suction with the 
mouth applied at the end of e. 

C0 2 a Product of Respiration. — App. — 
Straight or bent glass tube about 1 ft. long. 
Mat. — Lime H 2 in a beaker (or other glass 

Fig. 26.— To Show that C0 2 vesse1 )- 

is a Product of Combus- Exp. 167.— Breathe through the tube into 

tion. the lime H 2 0. The presence of C0 2 is 

shown by the whitening of the liquid. 

C0 2 a Product of Fermentation. — App. — 2 large test-tubes, porce- 
lain mortar, and pine splinter. Mat. — Molasses, 
baker's yeast, lime H 2 0, and H 2 0. 

Exp. 168. — Make a strong solution of molasses 
in H 2 0, and add a little yeast, preparing liquid 
enough to fill one of the tubes and cover the bottom 
of the mortar to the depth of half an inch. Fill 
the tube, invert it in the mortar and put the app. 
in a warm place. Fermentation will soon begin, 
and the C0 2 given off will displace the liquid in 
the tube. When the tube is full of the gas, close 
it with a piece of paper and remove it. Test the 
gas with a flame, then pour it carefully (not allow- 
ing any liquid to accompany it) into the other 
tube, and test with lime H 2 0. 

C0 2 is generally prepared for experi- 
mental purposes from marble or chalk (CaC0 3 ) by means of 
HCL 

To Prepare C0 2 . — App. — The generator used in preparing H, pneu- 




Fig. 27.— To Show 
that C0 2 is a 
Product of Res- 
piration-. 



CARBON GROUP. 9C> 

matic trough, and 1 1. and 2 half-1. wide-mouthed bottles. Mat. — 3 or 
4 g. CaC0 3 in lumps (marble may be used), and HC1. 

Exp. 169. — Arrange to collect the gas over H 2 0. Put the CaC0 3 in 
the generator, cover it with H 2 and add HC1. C0 2 is rapidly produced. 
' Fill all the bottles. 

Rea ction.— CaC0 3 + 2 HC1 = C0 2 -|- H 2 4- CaCl 2 (calcium 
chloride). 

Illustrations of Properties. 

Heaviness of C0 2 . — App. — The wire beam and paper vessel used in 
showing the lightness of H (p. 25) with the vessel balanced mouth up- 
ward. Mat— Bottle of C0 2 . 

Exp. 170. — Pour the C0 2 into the paper vessel, and the beam will turn 
with the weight of the gas. 

Dissolving of C0 2 ix B 2 0.—Mat.— Bottle of C0 2 and H 2 0. 

Exp. 171. — Put a little H 2 in the bottle of C0 2 , close the bottle with 
the hand or a cork, and shake it. C0 2 is absorbed. Open the mouth 
of the bottle under H 2 0, and more H 2 will enter. Then shake again 
and continue the operation until all the C0 2 is absorbed. 

Exp. 172. — Mark the position of the H 2 in the mouth of one of the 
bottles of C0 2 . and allow the bottle to remain inverted for several hours. 
The H 2 will absorb the gas and rise. 

Extinguishing of Flame by C0 2 . — App. — Lamp, tuft of cotton fast- 
ened to the end of a wire (or pine splinter), and tall beaker. Mat. — 
Bottle of C0 2 . alcohol, and short candle. 

Exp. 173. — \Vet the cotton with alcohol and thrust it into the gas. 
The light goes out. 

Exp. 174. — Light the candle, set it in the beaker, and pour the C0 2 
upon it. The light goes out. 

The effect of C0 2 on animal life is analo- 
gous to its effect on a flame. Since every 
respiration vitiates the air about us, it is 
highly important that the apartments in 
which we live be properly ventilated. The 
products of respiration and combustion as- 
cend; hence to ventilate a room properly 
there should be an opening near the ceiling 
to allow the vitiated air to pass out, and Fig. 28. — Pour- 

another near the floor to admit pure air. J? G 2 0N A 

1 Flame. 




100 



COMBUSTION. 



Uses and Tests. 
C0 2 is sometimes used for extinguishing fires, and the effect- 
iveness of "fire extinguishers" is due to this gas. "Soda 
water " is H 2 into which a large quantity of C0 2 has been 
forced. It contains no sodium compound. C0 2 is most easily 
detected by the lime-water test. 

Combustion. 

In ordinary combustion O from air combines with compounds 
of C and H to produce heat and light. The gaseous products 
are mainly H 2 vapor and C0 2 . 

In the burning of a candle, the tallow, reduced to an oil by 
the heat, is drawn up the wick into the flame, where it is con- 
verted into a gas. This gas forms the dark part 
of the flame, 1, (Fig. 29). O from the air combiner 
with the H of the gaseous compound, producing 
an intense heat. The carbon particles, which are 
at the same time set free, are made white-hot by 
this heat, producing the luminous part of the 
flame, the cone, 2. The hot carbon particles move 
outward and combine with O in the transparent 
cone, 3, C0 2 being formed. 

In the burning of an oil lamp, the combustible 

material, which in the burning candle is reduced 

to an oil by the heat of the flame, is an oil. The 

chimney, by confining the heated products of 

combusti on, causes them to ascend more rapidly, 

"" Parts of and hence causes a larger quantity of O to be 

a Flame. d ra wn in ^° the flame, thereby increasing the energy 

of the combustion. 

A lamp smokes when all the C of the burning material 
does not combine with O. Flat wicks are generally used be- 
cause they present so large a surface to the air. The superior 
light afforded by the "student lamp" is due to a large surface 
of wick exposed to a current >f air going to the interior of 
the flame, and to the peculiar form of the chimney, which de- 
flects the ascending outer air current upon the flame. 




CARBON GROUP. 



101 




In the burning of gas, the combustible material, which in 
the burning candle and lamp is reduced to the gaseous condi- 
tion by the heat of the flame, is a gas. 

To Show that the Dark Part of a Flame is a Combustible Gas, 

THAT THE LUMINOUS PART CONTAINS C, AND THE TRANSPARENT PART COj. 

— App. — Glass tube 6 in. long 
and kerosene lamp without 
chimney (or candle). 

Exp. 175. — Hold the tube in 
an inclined position with one 
end in the dark part of the 
flame. Gas will go up the tube. 2- 
Light it. 

Exp. 116.— Hold the end of f 
the tube in the luminous part of 
the flame and smoke (the C 
cooled) will pass off through it. 

Exp. 177. — Replace the funnel 
(Fig. 26) by a tube, and so ad- 
just the apparatus that the end 
of the tube just" reaches to the 
yellow part of the flame, then 
start the H 2 in the blower. 
The lime H 2 quickly whitens. 

To Show that the Luminosity of Flame is Due to Intense Heating 
of Carbon Particles. — App. — Alcohol lamp. Mat. — Finely powdered 
charcoal or iron filings. 

. Exp. 178.— Take the lamp lighted and the mat. into a dark room. 
The nearest objects can scarcely be seen, because, there being little C 
in alcohol, its flame is only slightly luminous. Sprinkle the powders 
into the flame, and it will become luminous. 

Since the central part of flame is a gas not burning, the 
luminous part must be hollow. 

To Show that the Luminous Part of Flame is Hollow. — App. — 
Piece of fine platinum wire 3 or 4 in. long, pine splinter, white paper, 
and lamp. 

Exp. 179. — Hold the wire across the flame just above the end of the 
wick. Only the sections of wire in the outer shell of flame will become 
red hot. Find where the flame is hottest by raising and lowering the wire 
in it. 




Fig. 30. — Gas from a Flame 



102 OXIDIZING AND REDUCING FLAMES. 

Exp. 180. — Hold the splinter across the flame just above the wick. 
Only the sections in the outer shell wUl be charred. 

Exp. 181. — Quickly lower the paper held with its plane horizontal 
upon the flame until it nearly touches the wick, and almost immediately 
remove it. A ring marking a cross section of the luminous part will 
be charred in the paper. 

The safety lamp is a lamp to u§e without danger in mines. 
It consists of an ordinary oil lamp enclosed in wire gauze. 

Principle of Safety Lamp. — App. — Piece of fine wire gauze and 
lamp. 

Exp. 182. — Lower the gauze into the flame. The flame will not pass 
through because its temperature is so much reduced by the gauze con- 
ducting away heat. 

When a safety lamp is carried into a place containing nre^ 
damp, the explosive mixture passes into the gauze cylinder 
and burns. The workman is thus warned of the danger. 

Oxidizing and Keducing Flames. 

Two well defined sections of a flame, called the oxidizing 
and the reducuuj flame, are much more prominently developed 
by means of the blow-pipe (p. 135). The oxidizing flame 



Fig. 31. — Oxidizing and Reducing Flames. 

(Fig. 31) is the yellowish outer cone b c ; the reducing flame, 
the blue cone a b. These are so named from the fact that 
metals heated in the oxidizing flame combine with O, and 
metallic oxides heated in the reducing flame part with O. 
The greatest heat is at the point of the blue cone. 

Action of the Blow-pipe Flames. — App. — Lamp, blow-pipe, and pin- 
cettes. Mat. — A copper cent. 



CARBON GROUP. " 103 

Exp. 183. — Produce a blow-pipe flame and hold the cent in the oxidiz- 
.ng part. It becomes coated with copper oxide. Now hold it in the 
reducing part and its brightness is restored. 

Carbon XHsulphide (CS 2 ). 
CS 2 is a colorless volatile liquid with an unpleasant odor. 
It has a very high refractive and dispersive power, and readily 
dissolves sulphur, phosphorus, fats, etc. It is prepared by 
passing S vapor over glowing coals. 

Cyanogen (CJV or Cy). 

CN is a colorless, poisonous gas, analogous to CI in many of 
its properties. It burns with a beautiful reddish flame. It 
is found in the gases of the blast furnace, and may be pre- 
pared by igniting the cyanides of certain metals. Compounds 
of CN with metals, etc., are called cyanides. 

To Prepare CN from Mercury Cyanide (HgCy.,). — App. — Piece of 
glass tubing about 8 in. long, and lamp. Mat. — \ g. HgCy 2 . 

Exp. 184. — Seal the tube at one end by drawing off the end in the 
flame, put in the cyanide, and draw out the other end until the opening 
is quite small. Then hold the tube nearly horizontal with the sealed 
end in the flame, and CX will be given off. Light the gas as it escapes. 
Mercury will be found in the tube. 

Reaction, — HgCy 2 = Hg + 2 Cy. 

Hydrocyanic acid (HCy, Prussic acid) is a colorless, poison- 
ous liquid, which readily dissolves in H 2 and alcohol. It is 
so poisonous that one drop if swallowed will cause instant 
death. It is prepared by the action of an acid on a metallic- 
cyanide. HCy combines to form cyanides. 

SILICON (Si) 28. 
Si has three allotropic forms, amorphous, graphite-like, and 
crystalline. It is next to O in abundance, forming about one- 
fourth by weight of the rocky crust of the earth. It is always 
found in nature combined with O, in quartz and silicates. 

Silicon Dioxide (Si0 2 ). 
The purest Si0 2 (silicic anhydride, silica) is quartz, a white, 
sometimes crystalline solid, next to diamond in hardness. It 



104 GLASS. 

is unaffected by the heat of the hottest blast furnace, but 
melts in the oxy-hydrogen flame ; it is insoluble in H 2 0, but 
dissolves in fluo-hydric acid and in sodium or potassium hy- 




il^t 



Fig. 32. — Quartz Crystals. 

drate. Agate, amethyst, and other stones used in jewelry, are 
forms of silica. Silica is found in plants, especially in the 
stalks of grains and grasses. 

Glass. 

Glass is a mixture of potassium (K) or sodium (Na) sili- 
cate, or both, with another silicate or other silicates. Window 
glass, and crown glass, used for optical purposes, are silicates 
of Na and calcium (Ca). Plate glass is a silicate of Na or K, 
Ca, and aluminum (Al). Ordinary bottle glass is a silicate of 
Na, Ca, Al, and iron. Bohemian glass, used for chemical 
purposes, is a silicate of K and Ca. Flint glass is a silicate 
of K and lead. " Crystal" is a pure flint glass used for opti- 
cal purposes and table ware. " Strass" the basis of artificial 
gems, is a flint glass with the proportion of lead increased. 
Soluble glass or water glass, is a silicate of K or Na or a mix- 
ture of them. It is a liquid soluble in H 2 0.* 

Glass is colored with certain metallic oxides, either by mix- 
ing them with the melted silicates, or by fusing them on the 
surface of the manufactured article. Thus, the oxides of iron 
give a dull green or brown, copper monoxide, ruby red, cobalt 
monoxide, a deep blue, and arsenious oxide, the dull white of 
lamp shades. 

*It is not known which of the ancient nations discovered the process 
of making glass, but the oldest specimens are Egyptian, and represen- 
tations of Egyptian glass-blowers on a tomb at Beni Hassan are sup- 
posed to date back to 3000 B. C. Glass coins were used in Egypt in the 
11th and 12th centuries. 



CARBON GROUP. 105 

In making blown glass-ware the workman collects a mass of the hot 
glass on the end of his blow-pipe, an iron tube 5 or 6 feet long, and 
blows through the tube, while he at the same time rotates it and changes 
its position. Window glass is made by blowing a cylinder, cutting it, 
and opening it into a sheet. Plate glass is cast on a flat metal table, and 
after being annealed, is ground and polished. A large amount of glass- 
ware for household purposes is made in moulds. Tubes are made by 
drawing out hollow cylinders. 

TIN (Sn) 118. 

Sn is a silver-white, lustrous, very malleable metal Avith a 
crystalline structure. Sp. gr. 7.29. In bending a bar of the 
metal, the breaking of the crystals produces a peculiar sound, 
called the "cry of tin." Sn dissolves readily in HC1. It 
does not tarnish in air. 

Sn is rarely found free in nature, and its ores occur only in 
a few localities. The principal source of the metal is the 
dioxide called tin stone, the richest mines of which are those 
of Cornwall, England, and Malacca, India. It is obtained 
from the ore by reduction with C. 

The lustre of Sn and its unchangeableness in air render it 
valuable for coating other metals. Tin-ware is made of sheet- 
iron coated with tin. This tin-ware coating often contains 
lead, which may be a source of slow poisoning, since the acid 
of vinegar forms with lead poisonous lead acetate. 

Ordinary pins are made of brass wire and brightened b} r a 
thin coating of Sn. Sn is a constituent of several useful 
alloys. Plumber's solder and pewter are composed of Sn and 
lead, bronze and bell-metal, of Sn and copper, and Britannia 
metal, of Sn, copper, and antimony. 

Exp. 185. — To test for lead in tinned iron (tin), put a drop of strong 
acetic acid on the surface to be tested and add to it a drop of a solution 
of potassium iodide. If lead be present, there is formed in two or three 
minutes a yellowish spot of lead iodide. Or moisten the surface to be 
tested with H 2 S0 4 . If lead be present the moistened spot becomes 
brown. 

5* 



106 COMPOUNDS OF TIN. 

Compounds. 

Stannic oxide (Sn0 2 ) and stannous chloride (SnCL, tin salt), 
prepared by dissolving Sn in HC1, are the most important 
compounds of the metal. SnCL is much used in dyeing. 

The other elements of the C group are rare. Titanium 
possesses the peculiar property of combining with N in 
several proportions. Its most abundant source is Titaniferous 
iron. Zirconium, has the allotropic forms of silicon, which it 
closely resembles. It is found only in rare minerals. 



PRACTICAL QUESTIONS. 

1. Why is only a limited amount of air admitted to the wood in the 
preparation of charcoal ? 

2. Why does not an alcohol flame "smoke" a surface with which it 
comes in contact? 

3. How much C0 2 would the burning of 1 gram of CO produce ? 

4. Name some natural carbonates. Some artificial. Some com- 
pounds that are not carbonates. 

5. There are about 3 volumes of C0 2 in 10,000 volumes of air. "Why 
does the amount vary? 

»;. How much heavier is limestone than lime? 

7. How many grams of marble are required to produce 1 gallon of 
C0 2 ? 

8. What is the blaze of a fire? Why do not fires always blaze? 

9. What is the chemistry of smothering out a fire? 

10. Why does a draft of air cause a fire to burn more brightly and a 
lamp to smoke ? 

11. Why is the heat of flames increased by the use of the blow-pipe 
or bellows? Would blowing the flame with the breath increase it? 

12. Of what advantage are the tall chimneys of certain manufac- 
tories ? 

13. Why do shavings kindle more quickly than blocks ? 

14. Why is there a great waste of material in ordinary combustion? 

15. Why will a match just kindled not light a lamp ? 



ORGANIC CHEMISTRY. 



There is no essential distinction between inorganic and or- 
ganic chemistry. The latter term is used simply for conveni- 
ence in classification. It was introduced when it was supposed 
that the substances formed in animals and plants could not be 
produced without the intervention of life. Although multi- 
tudes of such substances are now produced artificially, yet 
since most of them are derived from organic substance, and 
since they possess characteristics of composition and structure 
not belonging to other classes of compounds, it is convenient 
to include them under the head of organic chemistry. 

HYDROCARBONS AND DERIVATIVES. 

The hydrocarbons are compounds consisting only of C and 
H. They are arranged in series, each term differing from the 
preceding by the quantity CH 2 . Many of them are produced 
by the destructive distillation of wood, coal, and other organic 
substances. Only a few of them are discussed in this treatise. 
The most important series of hydrocarbons are the paraffines 
(or methanes), olefines, and aromatic compounds; the most im- 
portant derivatives are the camphors, resins, alcohols, and ethers. 

Paraffines (CH 4 , &H,, C S H 8 , etc). 

General Formula, C n H-2, n -\-i- 

Methane (CH 4 ). 
CH 4 (methyl hydride, marsh gas) is a colorless, very light, 
combustible gas. Its burning produces C0 2 and H 2 0. It is 
a product of decomposing vegetable matter in the mud of 
stagnant waters, and is often disengaged in coal mines, where, 
mixed with air, it produces the dreaded fire damp. It may be 
prepared by heating a mixture of sodium acetate and sodium 
hydrate. 



108 PETROLEUM. 

Burning of CH 4 . — App. — Large glass jar. 

Exp. 186. — Fill the jar with CH 4 at the nearest pond, and bring a 
lighted match to its mouth. The gas burns with a yellow flame. CH 4 
thus collected contains some C0 2 . 

Chloroform, CHC1 3 , which may be regarded as derived 
from methane, three atoms of H being replaced by three of 
CI, is a colorless, heavy, volatile liquid, prepared by distilling 
a mixture of bleaching powder and dilute alcohol. It is used 
in medicine as an anaesthetic, and in the arts as a solvent for 
the alkaloids, rubber, resins, etc. 

Petroleum. 

Petroleum, which is a mixture of paraffines, is a greenish, 
oily, combustible liquid. It is a natural product, found in 
great abundance in Pennsylvania and various other parts of 
the world. It is supposed to have been formed either by the 
spontaneous distillation of organic matter contained in the 
rocks (sandstone) where it is found, or by the condensation by 
these rocks of gas originating in much deeper strata. It is 
generally obtained by boring wells through the rocks under 
which it lies. 

Kerosene. — The term kerosene, originally used to desig- 
nate an oily product obtained from the distillation of bitumi- 
nous coal, etc., is now applied to refined petroleum. The 
refining of petroleum consists in first heating it by steam pipes 
passing through it, and then subjecting it to a gradually in- 
creasing higher temperature. The steam heating drives off a 
light gas which is used as fuel, and the subsequent heating 
furnishes the following products ; 1st, gasolene (a very light 
liquid); 2d, benzine; and 3d, burning oil (kerosene), which 
forms from 70 to 72 per cent, of petroleum. 

Paraffin, — Paraffin, which is also a mixture of paraffines, 
is a white waxy solid, easily melting, and only slightly affected 
by acids or alkalies. It is found in nature in coal beds, and 
in some varieties of petroleum from which the paraffin of 
commerce is generally prepared. Cosmoline contains a mix- 
ture of soft paraffines. 



HYDROCARBONS AND DERIVATIVES. 109 

Olefines (C,H i9 C 3 H 6 , C*m, etc). 

General Formula, C n H in . 

Ethylene (C 2 H 4 ). 

C 2 H 4 (olefiant gas, so named because it forms an oily com- 
pound with CI) is a colorless, very combustible gas, burning 
with a luminous name. It is prepared from H 2 S0 4 and alcohol. 

To Prepare C 2 H 4 and Show its Burning. — App. — A qr.-l. flask with 
cork and delivery tube, half-1. wide-mouthed bottle with cover, pneu- 
matic trough, retort stand with gauze, and lamp. Mat. — Alcohol, 
H 2 S0 4 , H 2 in a beaker, and clean sand. 

Exp. 187. — Arrange to collect the gas over H 2 0, put 25 c.c. of alcohol, 
100 c.c. of H 2 S0 4 , and some sand, to prevent frothing, in the flask, and 
heat. After the air is expelled from the apparatus, fill the bottle with 
the gas. Exp. 188. — Close the bottle with the cover, and put it erect 
on the table ; then light the gas and slowly pour H 2 into the bottle to 
force it out. 

Aromatic Compounds (C 6 IT 6 , C-H*, C^H^, etc). 

General Formula, O n n in — & . 

Benzene or Benzol (C 6 H 6 ). 

Benzene is a colorless, volatile liquid, producing a very com- 
bustible vapor. It is a valuable solvent, dissolving sulphur, 
caoutchouc, wax, and fatty substances. It is found in coal- 
tar, from which commercial benzene is obtained by distillation. 
Benzine, used for removing grease, is obtained as a secondary 
product in refining petroleum. 

Nitro-benzene is a yellow, oily liquid, with the smell of bit- 
ter almonds, prepared by the action of strong HjTO 3 on 
benzene. 

Aniline (C 6 H 7 N) is a liquid of light yellow color, becoming 
brown by long exposure to air and light. It is generally pre- 
pared by distilling nitro-benzene with iron filings and acetic 
acid. 

The aniline colors, which embrace all the common colors, 
are prepared by the action of various substances on aniline. 
These colors are very intense and beautiful. The aniline dyes 



HO ESSENTIAL OILS. 

are obtained from a mixture of aniline and toluodine, a sub- 
stance derived from coal tar. 

Carbolic Acid. — Carbolic acid, or phenol, when pure is a 
colorless, crystalline solid, which will absorb moisture and 
form an oily liquid. It has the odor of creosote, which it 
closely resembles, and has the property of preserving organic 
matter from decay and preventing the spread of infectious 
diseases. It is prepared from coal tar by distillation, and is 
much used as an antiseptic. 

Exp. 189. — Prepare CHC1 3 , using distilling app. (p. 27) and 40 c.c. 
H 2 0, 2 c.c. alcohol, and 10 g. bleaching powder. Distill until 2 c.c. 
have passed over. The CHC1 3 will be in the bottom of the receiver. 
Exp. 190. — Prepare nitro-benzene, heating 2 or 3 c.c. of HX0 3 with a 
tew drops of benzene. Exp. 191. — Dissolve a crystal of aniline red in 
alcohol, and pour the solution into a large bottle of H 2 0. 

Essential Oils (C 10 I?u). 

The essential oils are oily, inflammable substances, nearly 
insoluble in H 2 0, and differing from the fatty oils by reason 
of their volatility and odors. They are soluble in alcohol, 
the solutions forming essences. The oil of turpentine, of 
cloves, of lemon, and of juniper, are essential oils. These oils 
are obtained from plants, occurring generally in the roots, 
leaves, petals, or fruit. They are generally prepared by dis- 
tilling the plant substance with H 2 0, the oil passing over with 
the steam and separating from the condensed H 2 0. Oil of 
turpentine readily dissolves fixed oils and resins, this property 
rendering it valuable in the preparation of paints and var- 
nishes. 

Dissolving of, and Solvent Action of Oil of Turpentine. — App. — 
2 test-tubes and lamp. Mat. — Oil of turpentine, alcohol, and a little 
shellac. 

Exp. 192. — Put some of the oil and some alcohol in a tube and shake. 
The oil dissolves. 

Exp. 193. — Put the shellac and some of the oil in a tube and heat. 
The shellac dissolves. 

To Prepare Oil of Turpentine. — App.— Distilling app., etc. (p. 27). 
Mat. — 4 or 5 g. turpentine (a resinous substance which exudes from pine 
trees) and H„0. 



HYDROCARBONS AND DERIVATIVES. HI 

Exp. 194. — Put the turpentine and some H 2 in the retort and heat. 
The oil forms a layer on the H 2 in the condenser. 

To Prepare Oil op Cloves. — App. — Distilling app., etc. Mat. — 5 g. 
ground cloves. 

Exp. 195. — Put the cloves and several times its bulk of H 2 in the 
retort and heat, continuing the distillation until half the liquid has 
passed over. The oil collects in drops in the bottom of the condenser ; 
it separates more completely when the liquid stands for several hours. 
The condensed H 2 has the odor of the oil. " Perfumed waters," as 
rose water, and Florida water, are prepared in this way. 

Camphors and Hesins. 

Common camphor (C 10 H 16 O) is a white, volatile, combustible 
solid, readily soluble in alcohol, the solution forming "spirits 
of camphor." It is obtained by distilling with H 2 the wood 
of the camphor tree, which is indigenous to China and Japan. 

Resins are generally amorphous, brittle, combustible solids, 
• soluble in alcohol, the solutions forming varnishes. They are 
obtained from viscid exudations from plants. Common resin 
is the residue in the preparation of oil of turpentine. Shellac, 
copal, and mastic are resins. Grinn resins are milky juices of 
plants solidified by exposure to air, as assafcetida, gamboge, 
myrrh. Balsams are certain exudations from trees, consisting 
mainly of a mixture of resins and essential oils, as Canada 
balsam. 

Caoutchouc and Gutta Percha are the hardened juices of sev- 
eral tropical trees. The former only is elastic. Vulcanized 
rubber is a combination of these products with S. Hard rub- 
ber (vulcanite, ebonite) is prepared by subjecting vulcanized 
rubber to heat and pressure. It is used for combs, buttons, 
and many other purposes. 

There are two well known fossil resins, amber and asphalt 
(asphaltum, or mineral pitch). The former is found on the 
coast of the Baltic Sea, and the latter in the region of the 
Dead Sea and in many other places, having probably been 
formed from petroleum. 



112 ETHERS. 

Alcohols. 

The terra alcohol is given to a class of compounds, the most 
important of which is common alcohol, the intoxicating con- 
stituent of various drinks. The alcohols are all composed of 
C, H, and O, and may be regarded as derived from the hydro- 
carbons by the replacement of one or more H atoms by the 
group OH. 

Methyl alcohol (wood spirit,) which is much like common 
alcohol, is prepared by distilling wood. It is used extensively 
in the preparation of varnishes. 

Ethyl alcohol ((C 2 H 5 )HO, common alcohol, spirits of wine) 
is a colorless, volatile, inflammable liquid. Sp. gr. 0.79. It 
boils at 78° C, and has rarely been frozen. Proof spirit con- 
tains 50.8 parts by weight of alcohol to 49.2 parts of H,0. 
Alcohol is prepared by distilling wines and other fermented 
liquors ; it is also obtained from Indian corn, molasses, and 
other substances. It is used in making tinctures, for preserv- 
ing zoological specimens, for heating in the chemical labora- 
tory, for dissolving resins, oils, etc., and for other purposes. 

Ethers. 

Ethers may be regarded as oxides of the alcohol radicals. 

Ethyl oxide ((C 2 H 5 )0, common ether) is a colorless, light, 
very volatile liquid which gives off a heavy, combustible 
vapor, and boils at 35° C. 

Volatility and Combustibility of Ether. — App. — Long narrow 
test-tube, mortar, and wide-mouthed bottle with cover. Mat. — Ether 
and warm and cold H 2 0. 

Exp. 196.— Nearly fill tne test-tube with cold H 2 0, and fill the re- 
mainder with ether. Put H 2 in the mortar and, closing the tube with 
the thumb, invert it in the mortar. The ether goes to the top. Now, 
pour hot H 2 on the tube, and the ether is converted into vapor ; then 
pour on cold H 2 and the vapor condenses to a liquid. 

Exp. 197. — Pour a little ether in the palm of the hand. The wet sur- 
face feels cold by the evaporation of the liquid. 

Exp. 198. — Put a few drops of ether in the bottle, and allow the bot- 
tle to stand loosely covered for about a minute. Then bring a flame to 
its mouth. The ether vapor burns. 



CARBHYDRATES. 113 

Sulphuric ether is prepared by heating alcohol with H 2 S0 4 , 
and acetic ether generally by distilling an acetate with HoSCX, 
and H 2 0. Ether is much used in medicine as an anaesthetic. 

To Produce Ether. — App. — 2 test-tubes and lamp. Mat. — Alcohol, 
H 2 S0 4 , sodium acetate, and H 2 0. 

Exp. 199. — Put equal quantities of alcohol and H 2 S0 4 in one tube, 
and a little sodium acetate, H 2 and H 2 S0 4 in the other, and heat the 
tubes gently. The two ethers, recognized by their odors, will be pro- 
duced. 

Aldehydes and Acids. 

The Aldehydes and some acids are formed by the oxidation 
of alcohols, the former with a much less amount of O than 
the latter. The aldehydes are somewhat like acetic aldehyde, 
commonly designated simply aldehyde, a pungent, volatile 
liquid prepared from common alcohol. 

Chloral is a thin, colorless, oily liquid, which forms with a 
small quantity of H 2 a white, crystalline mass called chloral 
hydrate, much used in medicine to produce sleep. It is pre- 
pared by the action of chlorine on alcohol. 

CARBHYDRATES. 

The Carbhydrates contain H and O in the proportion in 
which these elements exist in H 2 0. They are very similar in 
composition and are easily converted into one another. They 
are very widely distributed in the vegetable kingdom, and 
form the most valuable constituent of plant life. The most 
important carbhydrates are the sugars, starch, cellulose, and 
gums. 

Sugars. 

Sucrose. — Sucrose (C 12 H 22 O n , cane sugar), the chief sugar 
of commerce, varies in color from white to dark brown, has a 
crystalline structure, and is very soluble in H 2 0. Rock candy 
is one of its crystalline forms. Barley sugar is melted sucrose, 
and caramel, used for coloring soups, wines, etc., is sucrose 
heated until it becomes brown.* 

* Sugar is not mentioned before the beginning of the Christian era. 
According to Pliny, it was used in his time as a medicine, and when it 



114 SUGARS. 

Exp. 200. — Prepare rock candy, making a very strong solution of 
sugar. Exp. 201. — Prepare barley sugar, heating just sufficiently to 
melt the sugar ; also caramel. Pour them on a piece of white paper to 
cool. 

Sucrose occurs in many plants, but is manufactured chiefly 
from the juice of sugar-cane, beet-root, and sugar-maple. In 
extracting sugar from cane, the juice is pressed out of the 
canes by passing them between rollers. Milk of lime is added 
to the liquid to correct its acidity and combine with impuri- 
ties ; it is then concentrated by evaporation in open pans, and 
on cooling the sugar crystallizes. The mother liquor, which 
is molasses, is drawn off, and the crystalline product is brown 
sugar. 

Crude sugar is refined by dissolving it in H 2 0, filtering the 
solution through animal charcoal to remove impurities and 
coloring matters, evaporating the solution and crystallizing. 
The solution is evaporated in vacuum pans (vessels from which 
the air and steam are partly exhausted) in order to boil it 
rapidly at a low temperature. The crystalline mass is drained, 
either by rotating it rapidly in a horizontal cylinder of stout 
netting (centrifugal machine) to form granulated sugar, or in 
moulds to form loaf sugar. The mother liquor is molasses. 

Glucose. — Glucose (C 6 H 12 O c , dextrose, grape sugar) has 
generally a brownish-yellow color, and is much less soluble 
and much less sweet than cane sugar. It is found in grapes, 
figs, and many other fruits, and is prepared by the long con- 
tinued boiling of starch with a dilute acid. 

Aimjlo.se. — Amylose (starch sugar) is a mixture of dex- 
trose, dextrine, and other products, and is prepared by boiling 
starch with dilute H 2 S0 4 . It is manufactured in immense 
quantities under the name of glucose from Indian corn. It is 
used in making alcohol, in adulterating table syrup and cane 
sugar, for candies and other purposes. 

Exp. 202. — To detect amylose or glucose in cane sugar, put equal 

came into use for other purposes it was long a luxury only of the rich. 
Sugar-cane, which is nowhere found wild, is probably a native of 
Bengal. 



CARBEYDRATES. 115 

quantities of pure sugar and of the sugar to be tested in small beakers, 
and set the beakers in hot H 2 0- If the suspected sugar contains amy- 
lose or glucose, it will melt much more quickly, and look much more 
like molasses, than the other ; and when the syrups cool it will remain 
liquid, while the pure sugar will become solid. 

Fermentation, 

Fermentation is the decomposition of certain substances 
under the influence of H 2 0, air, and warmth. It is caused 
by the action, not understood, of living germs, which are gen- 
erally introduced in the form of yeast, a ferment, into the sub- 
stance to hasten the decomposition. These germs exist in air, 
and under favorable conditions, fermentation takes place with- 
out the addition of a ferment. 

There are two stages of ordinary fermentation, the alcoholic 
and the acetic. Alcoholic fermentation changes grape sugar 
into, mainly, C0 2 (Exp. 168) and alcohol. 

To Show that Alcohol is a Product of Fermentation. — App. — Dis- 
tilling app., etc (p. 27). Mat. — A fermented liquid prepared by sweet- 
ening H 2 with molasses, adding some yeast, and letting the liquid 
stand in a warm place until it ferments. 

Exp. 203. — Put the liquid in the retort and heat with a low flame. 
Continue the distillation until one-third of the liquid has passed over. 
Re-distil the condensed liquid, which is a mixture of alcohol and H 2 0, 
by supporting the retort in H 2 and heating the H 2 0. The product 
now obtained contains sufficient alcohol to be detected by its taste and 
smell, and probably by its flame. Prove the presence of alcohol in a 
fermented liquor, as wine or cider. 

Acetic fermentation, by the absorption of O from air, 
changes alcohol into acetic acid and H 2 0. It is a continua- 
tion of the alcoholic, as in the changing of cider to vinegar. 

Alcoholic Liquors. 

Fermented Liquors, — Wine is the fermented juice of the 
grape. No ferment is added, the juice being simply exposed 
in vats to air. Sweet wine is produced by checking the fer- 
mentation, and champagne, by bottling the fermenting liquid, 
thus causing it to retain the C0 2 . 

Beer is a fermented infusion of malt. Malt, which is gen- 



116 CELLULOSE. 

erally made from barley, is prepared by soaking the grain, 
putting it in a warm place to sprout, and drying the sprouted 
grain at a high temperature. The malt is crushed and heated 
with H,0 to about 77° C. for several hours, the clear liquid 
(wort) is then strained off and boiled with hops, then yeast is 
added, and it is placed in the fermenting vessels. 

In sprouting, there is formed in the seed an active ferment 
called diastase which, in. heating the malt with H 2 0, converts 
the starch into sugar and dextrine. The hops give to beer its 
bitter taste. Fermented liquors contain from 1 to 25 per cent. 
of alcohol. 

Distilled Liquors. — Distilled liquors are prepared by dis- 
tilling certain fermented liquids. Brandy is made by distilling 
wine, whiskey by distilling a wort generally obtained from 
corn or rye. Distilled liquors contain from 40 to 50 per cent, 
of alcohol. 

Starch. 

Starch (C 6 Hi O 5 ) is a white powder composed of round or 
oval microscopic grains. It is insoluble in H 2 0, but when 
heated in H..0 to about 60° C. the grains swell and burst, 
forming the jelly-like substance used for laundry purposes. 
Starch is found in all plants, but is most abundant in grains. 
It is obtained by reducing the vegetable substance to a pulp 
and washing this on a sieve which allows the starch to pass 
through and retains the other ingredients. The test for starch 
is the formation of a blue compound with iodine (Exp. 61). 

Dextrine is a light yellow, gummy substance, soluble in H 2 0. 
It may be prepared by heating starch to about 160° C, or by 
boiling starch paste with H 2 S0 4 . It is the chief ingredient 
of the mucilage used on postage stamps. 

Cellulose. 

Cellulose (C 6 H 10 O5) is a white, tough substance which consti- 
tutes the largest part of plants, forming the outer wall of the 
vegetable cell. It is variously modified in different varieties 
of wood, in pith, bark, and fruit. Cotton and linen are 



ACIDS. 117 

almost pure cellulose. We use cellulose in the form of wood, 
thread, paper, etc., and its decomposition gives us illuminating 
gas, charcoal, oxalic acid, and other substances. Parchment 
paper is prepared by dipping unsized paper into strong H 2 S0 4 . 

Gun-cotton (pyroxylene) closely resembles cotton-wool in 
appearance, but is very explosive and burns without smoke or 
residue. It is prepared by soaking cotton or other cellulose 
in a mixture of HX0 3 and H 2 S0 4 , and letting it dry. Part 
of the H of the cellulose is replaced by N0 2 . 

Celluloid is a hard, tough, elastic substance, prepared by 
mixing gum camphor with a pulp of gun-cotton and com- 
pressing the mixture at a high temperature. It is used for 
combs, knife-handles, and various other purposes. 

Collodion is a colorless, syrupy liquid, prepared by dissolv- 
ing gun-cotton in a mixture of alcohol and ether. When it 
is spread over a surface exposed to air, the solvent evaporates, 
leaving a thin, adhesive membrane. This property of col- 
lodion renders it valuable in photography. 

Exp. 204. — Prepare dextrine by heating powdered starch, stirring it 
until it becomes light yellow. Add H 2 0, which dissolves the dextrine, 
and filter. Add to the filtrate alcohol, which precipitates the dextrine. 
Exp. 205. — Prepare parchment paper, washing the paper thoroughly 
after it has been immersed in the acid. Exp. 206. — Ignite a tuft of 
gun-cotton. 

Gums. 

The Gums are vegetable masses which with H 2 form adhe- 
sive liquids. Gum Arabic, the best known of these substances, 
is produced by an acacia tree. Its solution is much used as 
an adhesive paste. Gum tragacanth differs from gum Arabic 
in merely becoming soft and gelatinous, not dissolving, in H 2 0. 

ACIDS. 
The Organic Acids, a large number of which are known, 
generally occur combined, but are sometimes found in a free 
state. The most important organic acids are acetic, oxalic, tar- 
taric, citric, malic, tannic, and salicylic. 



118 OXALIC ACID. 

Acetic Acid (CJLS)*). 

Acetic acid is the acid of vinegar, of Avhich it forms from 2 
to 4 per cent. At a temperature above 17° C. it is a colorless, 
intensely sour liquid ; below this temperature it becomes a 
transparent solid, called glacial acetic acid. Acetic acid is 
prepared by the oxidation of dilute alcohol ; also by the dis- 
tillation of wood. The crude distillate is called pyroligneous 
acid. Compounds formed by the action of acetic acid on 
metals, etc., are called acetates, as lead acetate (sugar of lead), 
copper acetate (verdigris). 

To Prepare Pyroligneous Acid. — App. — Dry test-tube and lamp. 
Mat. — 2 or 3 pieces of matches. 

Exp. 207. — Put the wood in the tube and hold this horizontally in the 
flame of the lamp. The watery liquid formed is the acid. Prove its 
acidity with litmus paper. 

Vinegar, — Vinegar is made by the fermentation (acetic 
fermentation, p. 115) of malt, wine, cider, and other alcoholic 
liquids. The liquid is either stored in imperfectly closed ves- 
sels and slowly converted into vinegar, or subjected to the 
"quick vinegar process." This consists in causing the liquid 
to trickle through beech-wood shavings soaked in vinegar. 
The action is greatly hastened by this process by reason of 
the vast amount of air-surface to which the liquid is exposed, 
oxidation taking place very rapidly. 

Oxalic Acid (CJIiOO* 

Oxalic acid is a white, crystalline, very poisonous substance, 
soluble in H 2 0. It occurs in the juices of the sorrel, rhubarb, 
and other plants, sometimes free, but generally combined. It 
may be prepared by the action of HN0 3 on starch or sugar ; 
it is produced commercially by heating sawdust with potassium 
or sodium hydrate. Important oxalates are potassium and 
calcium oxalates. 

To Prepare Oxalic Acid. — App. — Test-tube and piece of clean win- 
dow glass. Mat. — 1 g. starch and HN0 3 . 

Exp. 208. — Put the starch in the tube, cover it with HN0 3 and heat. 
When fumes of N0 2 no longer pass off, pour some of the solution on the 
glass. Crystals of the acid will soon form. 



ACIDS. 119 

Oxalic acid is much used in calico printing. It is fre- 
quently used to remove ink-stains and iron rust, a soluble 
oxalate of iron being formed. It is sometimes taken by mis- 
take for Epsom salt ; the antidote is a mixture of chalk or 
magnesia and H 2 0. 

Tartaric Acid (C 4 JET 6 6 ). 
Tartaric acid is a colorless, crystalline substance, soluble in 
H 2 0. It occurs in the juices of many plants. The com- 
mercial acid is prepared from argol, a hydrogen potassium 
tartrate, which forms on the inside of casks in which wine is 
fermenting. Cream of tartar is purified argol. Tartaric acid 
is much used iu dyeing and in medicine. Tartar emetic is an 
antimony potassium tartrate ; Rochelle salt, a sodium potassium 
tartrate. Rochelle powders consist of cream of tartar in one 
paper and hydrogen sodium carbonate in the other. 

Citric Acid, Malic Acid, 

Citric acid occurs in the orange, lemon, currant, and other 
acid fruits. It is prepared in large quantities from the juice 
of lemons. Magnesium citrate is used in medicine. 

Malic acid occurs in apples, pears, and many other fruits, 
also in tobacco leaves. It exists in rhubarb as potassium 
malate, crystals of which may be obtained by evaporating the 
juice of rhubarb stalks. 

Tannic Acids, Salicylic Acid. 

Tannic acids constitute the astringent principles of plants. 
They possess the important property of forming insoluble 
compounds with many organic substances, on which property 
their action in tanning depends. They occur in the bark and 
leaves of the oak and many other plants, also in various roots 
and seeds. Gallo-tannic acid is one of these acids obtained 
from gall-nuts. 

Salicylic acid is a white crystalline substance, somewhat sol- 
uble in H 2 0. It occurs in the bark of the willow and in oil of 
wintergreen. It is prepared by passing C0 2 through a heated 



[20 ALBUMINOIDS. 

mixture of pure carbolic acid and sodium hydrate and acidify- 
ing the residue (sodium salicylate). It is very valuable as an 
antiferment and disinfectant, and is used extensively in medi- 
cine. 

ALKALOIDS. 

The Alkaloids or organic bases, are bases of salts existing in 
plants, and embrace the plant poisons and medicinal princi- 
ples. They all contain N, have a bitter taste, and are alka- 
line. They are only slightly soluble in H 2 0, but dissolve in 
alcohol and produce soluble salts with acids. The most im- 
portant alkaloids are morphine, strychnine, nicotine, caffeine, 
and quinine. 

Morphine is one of the many alkaloids of opium, the dried 
juice of the poppy. It is very valuable in medicine as a 
sedative. 

Strychnine is an extremely poisonous substance obtained 
from the St. Ignatius bean and nux vomica, seeds of East 
India plants. It is used in medicine. 

Nicotine is the alkaloid of tobacco, the narcotic effects of 
which it produces. Caffeine (or theine) exists in tea and coffee. 
It forms about one per cent, of coffee. 

Quinine occurs with cinchonine in cinchona or Peruvian 
bark, from which it is extracted as a sulphate. The sulphate 
and hydrochloride are much used in medicine. 

ALBUMINOIDS. 

The Albuminoids all contain C, H, N, O, and S, but they are 
very complex, and their chemical relations are imperfectly 
understood. They constitute only a small portion of plants, 
but the chief portion of animals. They are, however, formed 
in the plant, and introduced into the animal as a part of its 
food. The most important albuminoids are albumen, fibrin, 
casein, and gelatin. 

Albumen is familiar as the white of eggs, of which it forms 
a large per cent. It is soluble in cold H..O, and is coagulated 
by heat (as seen in cooking an egg) and other agents. It 



FATS AND FIXED OILS. 121 

occurs abundantly in the serum of blood and much other 
animal substance. Vegetable albumen is a similar substance 
existing in vegetables. 

Fibrin forms a part of lean meat, from which it may be ob- 
tained by washing out the coloring matter. It is found in 
blood, forming the clot when blood coagulates. Vegetable 
fibrin is a similar substance found in gluten, the tough in- 
gredient of dough. 

Casein is familiar as the curd of milk, of which it forms a 
large part. It is coagulated by acids and by rennet, the 
fourth stomach of the calf, and differs from albumen in not 
being coagulated by heat. Cheese is made by warming milk 
with rennet and pressing the curd that forms. The thin liquid 
remaining after the curd is formed is called whey. Legumin 
is a substance like casein, found in almonds, peas, beans, and 
many other seeds. 

Gelatin is a transparent, tough substance, soluble in warm 
H 2 0, the solution forming a jelly on cooling. It is obtained 
by boiling bones, tendons, and other animal substances in 
H 2 0. Isinglass is a pure gelatin made from the air-bladders 
of fishes. Glue is an impure variety, made chiefly from the 
refuse of hides. 

Pepsin is a constituent of gastric juice, and is the active 
agent in digestion. It is artificially prepared by the action 
of HC1 on the mucous membrane of the stomach (usually of 
the pig). 

FATS AND FIXED OILS. 
The Fats (which become oils when warmed) and fixed oils 
are mixtures chiefly of stearin, palmaiin, and olein, which are 
salts of glycerine and stearic, palmetic, and oleic acids. Stea- 
rin is the chief ingredient of tallow, palmatin, of palm oil, 
and olein, of olive oil. The fats and fixed oils are not volatile, 
and permanently stain paper and wood, leaving a "grease 
spot." They are insoluble in H 2 0, but soluble in ether and 
some other liquids. Some of them change when exposed to 



122 FATS AND FIXED OILS. 

air, undergoing a kind of fermentation and becoming " rancid." 
They are obtained from both animal and vegetable substances. 
Common fats are batter, tallow, and lard. Common oils are 
linseed oil, olive oil, and castor oil. 

Butter consists of the glycerides of butyric and other acids, 
and is obtained from cream by breaking its oily globules by 
churning, and causing them to collect in a mass. 

Linseed oil, called a drying oil, on account of its solidifying 
■when exposed to air from the absorption of O, is obtained from 
flax seed. It is highly valuable as an ingredient of paints and 
varnishes. The tendency of the oil to dry is greatly increased 
by heating it with litharge. Thus prepared, it is called boiled 
oil. Printer's ink is a mixture of lampblack and linseed oil, 
heated until it becomes thick. Olive oil (sweet oil) is obtained 
from the fruit of the olive ; castor oil, from the castor bean ; 
croton oil, from an East India plant ; cod-liver oil, from the 
liver of the cod-fish, and sperm oil, from spermaceti found in 
the brain of the sperm whale. 

Glycerine, — Glycerine is a sweet, colorless syrup, soluble 
in HoO, and itself an energetic solvent. It is prepared by 
decomposing fats with strongly heated steam, and is much used 
in medicine for external applications. Honey is frequently 
adulterated with it. Xitro-glycerine is an oily, very explosive 
liquid, prepared by allowing glycerine to run into a cooled 
mixture of strong HN0 3 and H 2 S0 4 . Dynamite is a mixture 
of nitro-glycerine and a porous substance, as silicious earth. 

Soap. — Soap is formed by the union of an alkali, generally 
potassium or sodium hydrate, with the acid, generally oleic or 
stearic, of a fat or an oil. The alkali of hard soap is sodium 
hydrate, that of soft soap, potassium hydrate. Olive oil is 
used for castile soap. Soap aids in cleansing by its alkali 
combining with the oily matter (not soluble in H 2 0) which 
the soiled article contains, to form another soap, soluble in 
H 3 0. 



COLORING SUBSTANCES. 123 

COLORING SUBSTANCES. 

The organic coloring substances of vegetable origin do not 
generally exist in a free state in the plant, but are in combi- 
nation, and are set free by fermentation and by the action of 
acids and alkalies. They may occur in almost any part of the 
plant, and also in the seed. Many of them have been pre- 
pared artificially. The most important of these substances are 
indigo, madder, logwood, and litmus. / 

Indigo is a blue substance, composed of the coloring matter, 
indigo blue, and various impurities. Indigo blue is insoluble 
in H 2 0, but dissolves in strong H 2 S0 4 , forming a deep blue 
solution. Indigo is obtained from several species of tropical 
plants. It is much used in dyeing and in making washers' 
blueing. 

Madder is a reddish powder which yields alizarin and other 
important coloring matters. It is prepared from the roots of 
a plant cultivated in various localities in the East, and in other 
places. It is a dye of great value, producing all shades of 
red, purple, brown, and even black. 

Brazil-wood, log-wood, and cochineal (a dried insect contain- 
ing the coloring matter carmine) are other red dyes. 

Litmus, which is used by the dyer as a red coloring matter, 
is obtained from various European lichens. Fustic, a West 
Indian Avood, and turmeric, an East Indian root, are common 
yellow dyes. 

Dyeing. 

To produce a fast color, or one that will not wash out, the 
coloring matter must combine with the fibres of the material. 
Only a few colors, as indigo, will do this ; hence a third sub- 
stance called a mordant, which has the property of fixing itself 
to the fibre and then uniting chemically with the dye, is gen- 
erally used. Alum, ferrous sulphate, and salts of tin, are 
common mordants.* 

* The most celebrated dye of antiquity was Tyrian purple, discovered 
as early as 1500 B. C. It was found in certain shell-fish of the Mediter- 
ranean. Each fish producing only a few drops, however, it was very 
dear, and was monopolized by royal families. 



124 DYEING. 

Action of a Mordant. — App. — Small beaker, retort stand, -with gauze 
and lamp. Mat. — Solution of logwood prepared by dissolving 1 g. ex- 
tract of logwood in 75 c.c. of H 2 0, strong solution of alum, (NHJHO, 
and piece of cotton cloth. 

Exp. 209. — Boil a piece of the cloth in half the logwood solution for 
several minutes, then wash it. Most of the dye will wash out. Now 
soak a piece of the cloth first in the solution of alum, then in the 
(NH 4 )HO, and boil it in the remainder of the logwood solution. The 
color of this piece will not wash out. 



QUESTIONS. 

[figures refer to pages.] 



INTRODUCTION. 

T. Give historical sketch. 8. Define matter. Atom. Molecule. Mass. 
What is the atomic theory? Define and give examples of substance. 
Organic substance. Inorganic substance. Physical properties of mat- 
ter. Chemical properties. Define Chemistry. 9. Define and give ex- 
amples of a chemical element. A chemical compound. How are com- 
pounds classified ? What is an acid ? A base ? A salt ? A radical ? 
A simple radical? A compound radical? Define chemical analysis. 
Ultimate analysis. Proximate analysis. Synthesis. What is a mixture ? 
How does it differ from a compound? Illustrate. 10, 11. What are the 
atomic weights of C, CI. Au, H, Fe, N, 0, K, Ag, Na, S, Zn? When 
and by whom was CI discovered ? H?N?0?P?K?Na? Give 
symbols of the common acids. 12. Define chemical affinity. Chemical 
action. 

12. How are symbols used in chemistry? How are the elements 
named ? How symbolized ? How are general compounds named ? How 
symbolized ? 13. Explain the use of figures used with symbols. How 
are equations used to express chemical reactions? Define the term 
formula. Rational formula. Empirical formula. Illustrate. Explain 
and illustrate the naming of binaries. 14. Of ternaries. Define and 
explain the use of bond symbols. Of graphic symbols. State the law 
of definite proportions. Illustrate. 15. What are the atomic weights? 
Molecular weights ? How is the percentage composition of a compound 
found? State the law of multiple proportions. Illustrate. Explain 
quanti valence. 16. What is meant by the terms, monad, dyad, triad, 
etc.? Give Ampere's law. Illustrate. 17. Give the law of volumes. 
Explain and illustrate. What is the product volume? The unit volume? 

17. Define and illustrate the term hydrate. Alkali. Amorphism. 18. 
Allotropism. Isomerism. Catalysis. Nascent state. Water of crys- 
tallization. Mother liquor. Effervescence. Deliquescence. 19. Efflo- 
rescence. What is a reaction ? A reagent ? An alloy ? An amalgam ? 
Define solution. What is a solvent ? How is solution shown ? How 
may solution be hastened ? 20. How is the hastening of solution 
(125) 



126 QUESTIONS. 

shown? What is a saturated solution? How is it made ? Define crys- 
tallization. How is it shown ? Why may crystals be produced by evap- 
oration ? How may their production in this way be shown? 21. Define 
precipitation. What is a precipitate ? How is precipitation shown ? 
Define filtration. How is it shown ? Define distillation. 22. Destructive 
distillation. How are substances heated on charcoal ? Define specific 
gravity. How is the sp. gr. of a solid found ? How shown ? How is 
the sp. gr. of a liquid found ? 

INORGANIC CHEMISTRY. 

Hydrogen 7 . 23. Symbol. Atomic weight. Properties. Occurrence. 
Preparation. 24. Write and explain the equation expressing the re- 
action. How is the lightness of H shown? 25. The diffusibility? The 
H flame? The singing flame ? 26. The formation of H 2 by burning H ? 
What precaution should be taken in making experiments which re- 
quire II to be lighted ? How is it shown that H does not support com- 
bustion? Uses and tests. Water. Symbol. Properties. Occurrence. 
Composition. 27. What are the impurities of H 2 0? How is it purified? 
Describe the process of distillation. 28. How is the purity of distilled 
H 2 proved ? androgen dioxide. 

Sodium Group. — Name the elements of this group and give their 
common characteristics. 

Sodium. 29. Symbol. Atomic weight. Properties. How is the de- 
composing of H 2 by Na shown ? 30. Occurrence and preparation. 
Sodium hydrate. Sodium chloride. Symbol. Properties. How may crys- 
tals of NaCl be prepared? Occurrence. 31. Preparation. Uses. What 
reason is there for believing that NaCl is a necessary article of food ? 
Soil, um sulphate. Sodium carbonate. Symbol, etc. 32. Describe Leblanc's 
process. What circumstance led to its discovery? Hydrogen sodium 
carbonate. Sodium nitrate. Sodium biborate. 

Potassium. 33. Symbol. Atomic weight. Properties. How is the 
decomposing of H 2 by K shown? Occurrence and preparation. Potas- 
sium hydrate. Chloride. Bromide. 34. Cyanide. Potassium carbonate. 
Symbol, etc. How is K 2 C0 3 obtained from wood ashes? Hydrogen 
potassium carbonate. Potassium nitrate. Symbol, etc. How is KN0 3 
shown to be an oxidizing agent? Potassium chlorate. 35. How is KC10 3 
shown to be an oxidizing agent? Tests for Na and K. Lithium and its 
compounds. 36. Silver. Symbol. Atomic weight. Properties. Occur- 
rence. Preparation. Give facts relating to the early use of silver. 
Silver chloride. 37. Silver nitrate. Tests. 

Chlorine Group. — Name the elements of this group and give their 
common characteristics. 



QUESTIONS. 127 

Chlorine. 38. Symbol. Atomic weight. Properties. Occurrence. 
Preparation. 39. Write and explain the equation expressing the reaction. 
How is the combining of CI and H shown ? The dissolving of CI in 
H 2 ? 40. The burning of oil of turpentine in CI ? The burning of 
antimony in CI ? CI as a bleaching agent ? 41. What is the action of 
CI in bleaching ? How is it shown that dry CI will not bleach ? Uses 
and tests. Hydrochloric acid. Symbol. Properties. Occurrence. 42. 
Preparation. Write and explain the equation expressing the reaction. 
How is the dissolving of HC1 in H 2 shown ? HC1 as a solvent ? Uses 
and tests. 43. Aqua regia. Fluorine. Symbol, etc. How is etching 
with F shown ? 44. Bromine. Symbol, etc. How is Br prepared from 
potassium bromide ? Iodine. Symbol, etc. 45. How is its vapor 
shown ? Its dissolving in alcohol ? Occurrence. Preparation. Uses 
and test. 

Oxygen Group. — Name the elements of this group and give their 
common characteristics. 

Oxygen. 46. Symbol. Atomic weight. Properties. What are ox- 
ides ? Occurrence. Preparation. 47. Write and explain the equation 
expressing the reaction. How does the Mn0 2 act in this process ? How 
are the Mn0 2 and KC1 separated ? How is the producing of flame in 
shown ? The burning of charcoal ? The burning of sulphur ? The 
burning of phosphorus ? What care should be taken in using P ? 48. 
How is the burning of iron wire in shown ? The effect of forced 
into a flame? Uses. Tests. 49. Ozone. Properties, etc. How is it 
prepared from P ? Test. 50. Combining of oxygen and hydrogen. The 
OH flame. The OH blow-pipe. How is a mixture of and H exploded? 

Sulphur. 51. Symbol. Atomic weight. Properties. What are sul- 
phides. How is the crystallization of S shown ? The preparation of 
plasticS? The dissolving of S ? 52. Occurrence. Preparation. Uses. 
Tests. Hydrogen sulphide. Symbol. Properties. Occurrence. 53. 
Preparation. Write and explain the equation expressing the reaction. 
How is the dissolving of H 2 S in H 2 shown ? The burning of H 2 S ? 
Uses and tests. Sulphur dioxide. Symbol, etc. 54. How is the extin- 
guishing of flame by S0 2 shown ? Bleaching with S0 2 ? Uses and test. 
Sulp>hur trioxide. 55. Sulphuric acid. Symbol. Properties. What are 
sulphates ? Give facts relating to the early production of the common 
acids. How is the corrosiveness of H 2 S0 4 shown ? The acidity ? How 
is it shown that heat is produced by the combining of H 2 S0 4 and H 2 ? 
That H 2 S0 4 contains lead sulphate? 56. Occurrence. Preparation. 
Explain the reaction. 57. Uses. Tests. 

Calcium Grronp. — Name the elements of this group. What are the 
alkaline earths ? 



128 QUESTIONS. 

Calcium. 58. Symbol, etc. Calcium oxide. Symbol, etc. How is 
the slacking of CaO shown ? 59. Calcium hydrate. Symbol, etc. "What 
is the difference between lime-water and whitewash ? What is bleach- 
ing powder? Calcium chloride. Calcium carbonate. 60. Calcium sulphate. 
Calcium phosphate. Barium and Strontium. Symbols, etc. How is 
green fire made? 61. Red fire? Lead. Symbol, etc. What danger 
is there in using water conveyed by lead pipes? Compounds. 62. Tests. 

Magnesium Group. — Name the elements of this group and give 
their common characteristics. 

Magnesium. 62. Symbol, etc. How is the Mg light shown? Com- 
pounds. 63. Zinc. Symbol, etc. How is the lead tree made? 64. 
Compounds. Cadmium. 

Aluminum Group. — Name the elements of this group. 

Aluminum. 64. Symbol, etc. Aluminum oxide. Symbol, etc. 65. 
How is logwood lake prepared ? Aluminum sulphate. Alum. Aluminum 
silicate. Symbol, etc. How are bricks, earthenware, and common pot- 
tery made ? What is porcelain. How are these wares glazed ? 66. In- 
dium, Gallium, Glucinum. 

Copper Group. — Name the elements of this group. 

Copper. GG. Symbol, etc. What reason have we for believing that 
copper was known at a very remote period ? 67. Oxides of cupper. 
Symbols, etc. How are Cu 2 and CuO formed? Copper suephate. 
Symbol, etc. How is it shown that the color of blue vitriol is due to 
H 2 0? Copper acetate. Tests. Mercury. 68. Symbol, etc. What 
mines supply the largest amount of Hg? Compounds. Symbols, etc. 
By what simple test can calomel be distinguished from corrosive sub- 
limate? 69. Tests. 

Nitrogen Group. — Name the elements of this group and give their 
common characteristics. 

Nitrogen. 69. Symbol. Atomic weight. Properties. Occurrence. 
Preparation. 70. How is it shown that N extinguishes flame ? Uses 
and test. Ammonia. Ammonium. Symbol. Properties. 71. How is 
the dissolving of NH 3 in H 2 shown ? The neutralization of an acid 
byNHj? Occurrence. Preparation. 72. Write and explain the equa- 
tion expressing the reaction. Uses. Ammonium chloride. Symbol, etc. 
How is the production of NH 4 C1 fumes shown ? Ammonium carbonate. 
Ammonium nitrate. 73. Tests. Nitrogen monoxide. Symbol, etc. 74. 
Write and explain the equation expressing the reaction which takes place 
in its preparation. Nitrogen dioxide. Symbol, etc. How is its affinity 
for shown ? Nitrogen tetroxide. Nitric acid. Symbol. Properties. 
How is HN0 3 as a solvent shown? 75. Occurrence. Preparation. 
Write and explain the equation expressing the reaction. Uses. How is 



QUESTIONS. 129 

etching done with HN0 3 ? Tests. 76. Air. Properties. Composition. 
How is air analyzed? How is it shown that air contains C0 2 ? 77. 
Permanence and purity of the air. 

Phosphorus. 77. Symbol. Atomic weight. Properties. 78. How 
is the solubility of P shown? The inflammability ? Red phosphorus. 
Luminous paint. Occurrence. Preparation. 79. Uses and Test. Hy- 
drogen phosphide. 80. Phosphorus oxides and acids. Arsenic. Sym- 
bol, etc. Hydrogen arsenide. Symbol, etc. 81. What is Marsh's Test? 
Arsenic trioxide. Symbol, etc. How are the volatilizing and crystalliz- 
ing of As 2 3 shown ? How is As produced from As 2 3 ? 82. Arsenic 
sulphides. Antimony. Symbol, etc. How is the burning of Sb shown ? 
Bismuth. 83. Vanadium. Uranium. 

Gold Group. — Name the elements of this group. 

Gold. 83. Symbol, etc. Why was gold probably the first metal 
known to man ? Why was it called the king of metals ? 84. What is 
hydraulic mining ? Auric chloride. Boron. Symbol, etc. Boric acid. 
Symbol, etc. 85. How is H 3 B0 3 obtained , from borax? How is the 
flame test for H 3 B0 3 made ? Thallium. 

Iron Group. — Name the elements of this group. 

Iron. 85. Symbol. Atomic weight. Properties. What evidences 
are there that Fe was known at a very earlj date"? 86. Varieties. 
What is puddling? Occurrence. Preparation. 87. Uses. 88. Oxides 
of iron. Hydrates. Sulphides. Sulphates. 89. How is dyeing with 
green vitriol shown ? Steel. Varieties. Properties. Tempering. Prep- 
aration. 90. Manganese. Nickel. Cobalt. 

Chromium Group. — Name the elements in this group. 

Chromium. 91. Symbol, etc. How is chrome alum prepared ? 
Molybdenum. Tungsten. 

Platinum Group. — Name the elements of this group. 

Platinum. 91. Symbol, etc. 92. What are platinum black and 
platinum sponge ? Indium. Osmium. Palladium. 

Carbon Group. — Name the elements of this group. 

Carbon. . 92. Symbol. Atomic weight. Diamond. Properties, etc. 
93. Give historical facts relating to the diamond. Large diamonds. 
Graphite. Charcoal. Properties. 94. How is the porosity of charcoal 
shown? Its property of destroying odors? Of destroying colors? 
The combining of C with ? 95. Preparation. Uses. Animal char- 
coal. Lamp black. Coke. 96. Gas carbon. Mineral coal. Goal gas. 
Carbon monoxide. 97. Carbon dioxide. Symbol. Atomic weight. Prop- 
erties. Occurrence. How is it shown that C0 2 is a product of combus- 
tion ? 98. Of respiration? Of fermentation ? Preparation. 99. Write 
and explain the equation expressing the reaction. How is the heaviness 



X30 QUESTIONS. 

of C0 2 shown ? The dissolving of C0 2 in H 2 ? The extinguishing of 
flame by C0 2 ? Explain the effect of C0 2 on animal life. How should 
a room be ventilated ? 100. Uses and tests. 

Combustion. What is the action of in ordinary combustion ? Ex- 
plain the burning of a candle. The burning of an oil lamp? When 
does a lamp smoke ? Why are flat wicks generally used ? To what is 
the superior light of the student lamp due? 101. Explain the burning 
of gas. How is it shown that the dark part of a flame is a combustible 
gas? That the luminous part contains C ? The transparent part, C0 2 ? 
That the luminosity of flame is due to the intense heating of carbon 
particles? That the luminous part of flame is hollow? 102. What is 
the .safety lamp? How is the principle of its action shown? What is 
the oxidizing flame? The reducing flame? Why are these flames so 
named? How is their action shown? 103. Carbon disulphide. Cyanogen. 
Silicon. Silicon dioxide. 104. Glass. Give facts relating to the early 
use of glass. Tin. 105. Symbol, etc. How is lead tested for in tinned 
iron ? 106. Compounds. 

ORGANIC CHEMISTRY. 

Hydrocarbons and Derivatives. — 107. What are the hydrocar- 
bons? How are many of them produced? Name the most important 
scries of hydrocarbons. The most important derivatives. 

I'akakfinks. How do they differ in composition ? Give general for- 
mula. Methane. Symbol, etc. What is fire damp? 108. How is the 
burning of CH 4 shown ? Chloroform. Petroleum. Kerosene. Paraffin. 
Olbfimbs. 109. How do they differ in composition ? Give general for- 
mula. Ethylene. Symbol, etc. How is its burning shown ? Aromatic 
Compounds. How do they differ in composition? Give general formula. 
Benzene. Symbol, etc. Benzine. Nitro-benzene. Aniline. Aniline col- 
ors. Aniline dyes. 110. Toluodine. Carbolic acid. Essential Oils. 
Symbol, etc. How is the dissolving of oil of turpentine shown? The 
solvent action ? How is oil of turpentine prepared? 111. Oil of cloves? 

Camphors and Resins. 111. Common camphor. Common resin. 
Gum resins. Balsams. Caoutchouc and Gutta Percha. Vulcanized 
rubber. Hard rubber. Amber. Asphalt. 112. Alcohols. How is the 
term alcohol used? What is the composition of the alcohols? Methyl 
alcohol. Ethyl alcohol. Symbol, etc. What is proof spirit ? Ethers. 
What is their composition ? Ethyl oxide. Symbol, etc. How is its vola- 
tility shown? Its combustibility? 113. Sulphuric ether, acetic ether. 
How may the production of ether be shown ? Aldehydes and Acids. 
How are they formed ? Acetic aldehyde. Chloral. Chloral hydrate. 

Carbliydrates. — 1 13. Composition, etc. Name the most important 



QUESTIONS. 131 

carbhydrates. Sugars. Sucrose. Symbol, etc. 114. How is crude 
sugar refined ? Glucose. Amylose. How is glucose or amylose de- 
tected in cane sugar? 115. Fermentation. What is fermentation? 
By what is it caused ? What is a ferment ? What are the two stages 
of ordinary fermentation ? How is it shown that alcohol is a product 
of fermentation? What is the action in acetic fermentation? Alcoholic 
Liquors. Wine. Beer. Malt. 116. Diastese. Distilled liquors. Brandy. 
Whiskey. Starch. Dextrine. Cellulose. 117. Gun-cotton. Cellu- 
loid. Collodion. Gums. 

Acids. — 117. Occurrence. Name the most important organic acids. 
118. Acetic Acid. Symbol, etc. What are acetates? How is the 
preparation of pyroligneous acid shown ? Vinegar. Oxalic Acid. 
Symbol, etc. Name two of the most important oxalates. 119. Tartaric 
Acid. Symbol, etc. Cream of tartar. Tartar emetic. Rochelle salt. 
Rochelle powders. Citric Acid. Malic Acid. Tannic Acid. Salicylic 
Acid. 

Alkaloids. — 120. Occurrence, etc. Name the most important alka- 
loids. Describe each. 

Albuminoids. — 120. Composition, etc. Name the most important 
albuminoids. Describe each. 

Fats and Fixed Oils. — 121. Composition, etc. 122. Give examples 
of common fats and oils. Butter. Linseed oil. What is boiled oil ? 
Printer's ink. Olive oil. Castor oil. Cod-liver oil. Sperm oil. Glycer- 
ine. Nitro-glycerine. Dynamite. Soap. 

Coloring' Substances. — 123. Origin, etc. Name the most important 
organic coloring substances. Describe each. Dyeing. How is a fast 
color produced ? What is a mordant ? Name some common mordants. 
What was the most celebrated dye of antiquity? Where was it found? 
How is the action of a mordant shown? 



APPENDIX. 



Apparatus. 

Balance and Weights. 

A balance sufficiently accurate for the requirements of common 
chemical experiments may be constructed as follows : 

Cut from a sheet of tin a strip f of an inch wide and 8 inches long, 
double it lengthwise, forming a strip of double thickness, bore a hole 
through the centre of this, and spread apart the sides so as to form a trough. 
Put a straight wire 10 inches long, and with notches filed in it near the 
ends, in the trough. Adjust the wire so that it will move endwise with 
considerable friction by closing the ends of the trough around it, and 
by binding it to the trough by means of a fine Avire through the hole at 
the centre. The trough and wire form the beam of the balance. 

Next drive a sixpenny nail through a strip of half-inch board (which 
may be a foot or more long and two inches wide) so that when the strip 
is leaned against a wall or other support the nail will project horizont- 
ally and be abont 6 inches from the base of the support, and reduce, by 
filing, a section of the upper side of the nail to an edge. This edge is 
to serve as a support for the beam. 

For pans use pieces of tin, 2\ inches square (the small disks in one 
end of fruit-cans make good pans). Bend two pieces of light wire, each 
G inches long, into a U-shape and solder them to the pans for handles, 
and attach the handles with heavy thread to the beam wire. Then 
place the beam on its support, and if it is not horizontal make it so by 
moving the wire. The balance is now complete. 

Metric weights are best adapted to chemical experimenting. Weights 
of sufficient accuracy may be made as follows : Balance a nickel five- 
cent piece, which weighs nearly five grams, with a piece of clean copper 
wire. Mark off the wire into five equal parts and cut off three one-fifth 
parts for one-gram weights and bend the remaining two-fifths part into a 
V-shape for a two-gram weight. Keep the five-cent piece for a, five-gram 
weight. Balance a gram weight with a piece of fine wire and cut this 
into ten equal parts for tenths of a gram. These weights, with two ad- 
ditional five-cent pieces, will be found sufficient for all the weighing 
required in making the experiments in this book. They should be kept 
in a box. To render the balance more convenient for finding specific 
(132) 



METRIC MEASURES. 



133 



gravities, make also a "weight of lead to fit the angle of the trough, that 
will balance one of the pans when the other is removed. The weights 
of the body whose sp. gr. is to be found are made by first weighing it in 
the usual manner, then removing one of the pans and balancing the 
beam with the leaden weight, and finally supporting the body by means 
of the pan thread in water and weighing again. 

Fig. 33 shows a balance of the best construction. The beams of such 




Fig. 33. — Chemical Balance. 

balances a^e provided with wedge-shaped fulcrums of hardened steel, 
called knife edges, which turn on pol- 
ished agate plates, and the beams are 
graduated for a small movable weight 
called a ride?\ which is used, in connection 
with the weights in the pan. to more ac- 
curately counterpoise the body which is 
being weighed. 

Fig. 34 shows the weights used with 
such balances. The gram weight and its 
multiples are made of brass, and the parts 
Fig. 34.— Metric Weights. of a £ ram of platinum. 

Metric Measures. 
Measures op Length. — The divisions of the metre (39.3685 inches), 
tV> too? an< ^ tto °f ^ ts length, called respectively the decimetre, the 
centimetre, and the millimetre, are used in chemistry. 




134 



APPARATUS. 



Make a metric rule as follows : Get a strip of wood or pasteboard 
3}| inches long. Divide one edge of this into 10 equal parts, and 
each of these divisions into 10 equal parts. The^ length of 
the entire scale will be a decimetre, the larger divisions will 
be centimetres, and the smaller ones millimetres. 

Measures of Capacity. — The litre (1., a cubic decimetre) 
and cubic centimetre (c.c.) are common measures. A cubic 
centimetre of distilled water at 4° C. (39.2° F.) weighs one 
gram. Make a measuring tube as follows : 

Select a long, narrow test-tube, support it upright on one 
of the scale-pans by tying it with a thread to the handle, and 
balance it with sand. Then weigh 10 grams of water in the 
tube and divide the part occupied by the water (making an 
allowance for the curved bottom) into 10 equal parts, making 
the division marks with a sharp file. Each section of the 
tube will then measure 1 c.c. 

Thermometers. 

Thermometers, with the scale marked on the tube or en- 
closed within an attached tube, and without 
a case, are required for chemical purposes. 
The reading of the Centigrade or of the Fah- 
renheit scale may be converted into that of 
the other by the following easily derived 
formulas : 

C. = 5( F ._3 2 o) ; F.=fC. + 32°. 
Thus 20° C. = f X20°+32° or 68° F. ; and 95° 
F. = f (95°— 32°) or 35° C. 





I 




a 


[ 




i 


\ 




S 
1 

C 

(V 

"o 
.1 

a 


\ 




I 




- 




S 

a 

o 


: 










: 




< 


, 





32- 
O- 



FlG.35.- 

Metric 
Scale. 



-/7-8 



Lamps. 

For common illuminating gas, which is the 
best and cheapest burning material for most 
laboratory purposes, the Bunsen lamp is used t 
It may be obtained of any dealer in chemical supplies. 
In the absence of gas, the common alcohol lamp is gen- 
erally used. An alcohol lamp may be made as follows : jp IG 36.-Ther- 
Get a common ink or mucilage bottle, and a cork that 
will fit it loosely. Make a hole through the cork, in- 
sert a short metal tube in it, and put several thicknesses of ordinary 
lamp wick, 3 or 4 inches long, through the tube. Fill the bottle with 
alcohol, insert the cork, and after the wick becomes wet with the alco- 



I 



mometric 
Scales. 



BLOW-PIPES. 



135 





C-( 



Fig. 38. — Low Tempera- 
tube Burner. 



hoi the lamp is ready to light. 
A tin cap may be made to fit over 
the mouth of the bottle, to pre- 
vent the evaporation of the al- 
cohol. 

The Fletcher burners, embracing 
a variety of forms of heating ap- 
paratus, and burning either illu- 
minating gas or kerosene, are 
excellently adapted to many 
laboratory purposes. 

The "Low Temperature Burner" produces a range of 
temperatures from warm air to red heat. The " Hot Blast Blow-pipe " 
(Fig. 39) has a vertical jet, v, to be used for the purposes of an ordinary 
alcohol or gas flame, and a blow-pipe jet, b. The tube supplying air is 
coiled around the gas tube, and both 
are heated by a flame / underneath. 
The vertical jet works on a hinge, so 
that it may be used to light the blow- 
pipe jet. 

A common kerosene lamp may be 
used for evaporating and other purposes 
for which low temperatures are re- 
quired. 

Blow-pipes. 

A blow-pipe is an instrument for 
conducting a small current of air into 



%M& 




Fig. 40. — Blow-pipes. 



Blast Blow- 



Fig. 39.— Hot 

PIPE. 

a flame. A common form of the instrument is a conical tube of brass, 
8 or 10 inches long, curved near the smaller end (A, Fig. 40). A blow- 
pipe may be easily made out of a glass tube. The air current should 
be produced entirely by the action of the cheeks, and may be made 
continuous (without being affected by breathing) by a little practice. 



136 



APPARATUS. 



Blowers. 

The simplest apparatus for forcing air through the blow-pipe is the 
hydrostatic blower (Fig. 41). Two large bottles with tightly-fitting 
corks, each containing a long and a short tube, are placed at different 
levels. The long tubes are connected by a piece of rubber tubing, and 
ihe short tube of the lower bottle is connected with the blow-pipe in the 
same manner. The upper bottle is filled with water, which will run 

into the lower bottle through the 
siphon formed by the connected 
tubes, and force the air through 
the blow-pipe. The water is started 
by pressure with the mouth through 
the tube a, or by suction through 
l» The blow-pipe should be 
clamped to an adjustable support. 
It may be fastened by a curved 
wire to the ring of the retort stand. 
An efficient foot-blower is shown 
in Fig. 42. 

Pneumatic Trough. 

A pneumatic trough is a vessel 
in which gases are collected over 
water. A common form of the 
apparatus is an oblong box of 
metal, wood, or glass, with a shelf 
resting on the sides for support- 




Hydrostatic Blower. 



ing the vessel in which the gas is 
to be collected. The vessel, if not 
too large, can be filled with water 
in the trough and lilted inverted 
upon the shelf. An ordinary 
bucket or small tub provided with 
a shelf answers for a large pneu- 
matic trough. For small receivers, 
as test-tubes, small bell glasses, 
etc., a dish about 6 inches in diam- 
eter and 3 inches deep, of japanned 
tin, earthenware, or glass, may be pjG 42 ._Fletcher Foot Blower. 
used as a pneumatic trough. A 

convenient receiver support for such a trough is a tin lid (as that of a 
candy jar) with a hole in the rim to admit the delivery tube and one in 




GAS-HOLDERS. 



137 




Fig. 43. — Pneumatic Trough. 



the top to admit the gas into the receiver. The receivers cannot gen- 
erally be filled in a small trough, but may be filled outside, and by care- 
fully covering them with a piece of 

paper or glass they may be placed on 
the shelf. Test-tubes may be kept up- 
right on the shelf by means of a ring 
of lead placed on the rim. A vessel 
full of gas may be lifted from the trough 
and the gas be securely retained by 
placing a saucer or other shallow dish 
under the vessel and lifting the dish (which will contain some water) 
and vessel together. 

Gf as -holders. 

A large bottle makes a convenient gas-holder for small quantities of 
gas. One of the bottles of the blower (Fig. 41) may be used for this 
purpose. Short pieces of rubber tubing, with ODe end plugged with a 
short glass rod, or tube sealed at one end, should be provided to close 
the outer ends of the tubes in the cork of the bottle, 

To put gas into the bottle, fill the 
bottle with water, insert the cork 
(with its tubes) and put on the stop- 
pers. Then invert the bottle and 
support it with its mouth under water 
in a pneumatic trough. This maybe 
done by means of a shelf with a hole 
3 or 4 inches in diameter, placed 
across the top of the trough. Then 
remove the cork and let it rest on the 
bottom of the trough, allowing the 
longer tube to remain partly within 
the bottle. The gas is then collected 
. by placing the end of the delivery 
tube in the mouth of the bottle. 

To transfer gas from the bottle to 
a smaller receiver, force the gas into 
the receiver, inverted full of water 
in the pneumatic trough, as air is 
forced into a flame. 

Another form of eas-h older is 

shown in Fig. 44. It consists of a p IG# 44 Gas-holder. 

cylindrical vessel containing water 

and a similar vessel inverted in the water. The inverted vessel is lifted 




138 



APPARATUS. 



and supported by a weight, "W. The vessels should be made of zinc, or 
galvanized iron. The inner one may be 1 foot in diameter and 2 feet 
high (of about 12 gallons capacity). The bottom of the inner cylinder, 
which should be convex outward, has a hole through its centre contain- 
ing a stop-cock. 

To put in gas, open the stop-cock and remove the weight, when the 
inverted cylinder will sink and become filled with water. Now connect 
the end of the tube delivering the gas, by means of rubber tubing, with 
the stop-cock, and attach the weight. The gas replaces the water in the 
rising cylinder. Extra weights may 
be added to relieve excessive pres- 
sure produced by an increase in the 
flow of gas. When sufficient gas 
has been collected, close the cock, 
remove the tube, and make the 
weight just sufficient to balance the 
cylinder. 

To transfer gas, connect the stop- 
cock by a rubber tube with the re- 
ceiver to which the gas is to be 
transferred, lessen the weight, and 
open the cock. A deep bucket, or 
any vessel of suitable size and shape, 
may be used for the outer cylinder 
of this apparatus. 

Fig. 45 shows another form of 
gas-holder. To put gas into it, 
open the tube t and fill the vessel 
with water through the funnel ; 
then close t and the stop-cock s, 
and replace the plug p with the 
tube delivering the gas. As the 
gas goes in the water goes out 
through o. To transfer gas, close o, 
connect the receiver into which the gas is to be put with t, put water in 
the funnel, and open s. 

Compressors and Pincettes. 

A compressor i? an apparatus used to check or stop the flow of a liquid 
or a gas through rubber tubing. A compressor well adapted to regulate 
the flow of a liquid or gas, also to serve as an efficient stop-cock, is the 




Fig. 45. — Gas-holder. 



RETORT STAND AND OTHER SUPPORTS. 



139 



screw compressor shown in Fig. 46 ; one adapted to quickly stop the flow 
is shown in Fig. 47. 





Fig. 46. — Compressor. Fig. 47. — Compressor. Fig. 48. — Pincettes. 

Pincettes are small brass or steel forceps used for holding objects in a 
flame. 

Retort Stand and Other Supports. 

Retort stands are used for supporting vessels over a flame. The rings 
vary in size and are adjustable on the rod. Beakers, flasks, retorts, 
and evaporating dishes, unless these vessels are very 
small, should not be placed in contact with the flame. 
The wire gauze is a piece of gauze from 3 to 5 inches 
square, made of fine brass wire. It is placed under a 
vessel to be heated in a flame for the purpose of dis- 
tributing the heat. The sand bath is a shallow, sheet- 
iron pan, containing sand in which the vessel is 
placed to be heated. It renders 
the heat very uniform. The 
water bath is a vessel containing 
water, on which, as a cover, the 
vessel containing the liquid to be 
heated is placed. The heating 

G ' S 9 tIn"d ET ° BT liquidisbythisarrangementkept f IG . 50 

below a certain temperature. 
The triangle is an equilateral triangle made of soft iron wire, for sup- 
porting small vessels on a ring of an iron stand over a flame. 

A good support for round-bottomed flasks is a broad hoop (which 





140 APPARATUS. 

may be cut from a round wooden box) wrapped with a strip of cloth. 
It should be of a size sufficient to prevent the flask from resting on the 
centre of the bottom. 

Filtering Apparatus. 

Filter paper is a porous, unsized paper, freed from inorganic impuri- 
ties. It is cut into disks called filters, having a diameter a little less 
than twice that of the funnel in which they are to be used. A filter is 
generally prepared for use by folding it twice so as to form a quadrant, 
and then opening it so as to leave three thicknesses of paper on one side 
and one on the other, thus giving it the form of a hollow cone. It is 
made to keep its place in and fit the funnel by wetting it with a little 
water. 

For rapid filtration, filters are sometimes folded as follows : First fold 
the disk as just described, then open the 
last fold, and the paper will have the form 
of a semicircle, Fig. 51. Now place the 
edges, cb and cd, on the crease, ce, and 
make the creases cr and cv. Then open the 
paper and fold each segment, cdv, eve , etc., 
so that the four new angles will be opposite 

5L_ T ° f I0W F ° LD " the f0Ur firSt formed - A filter thus made > 
called a ribbed filter, touches the funnel only 

at the alternate creases in the paper. 

The funnel is conveniently supported by means of a filter stand, but 

it may be supported in other ways, as in a ring 

attached to a shelf, or in the neck of a bottle. A 

filter should never be quite filled. 

Stoppers. 

Caoutchouc stoppers, because so compact and 
closely fitting, are much better than corks for chem- 
ical purposes. Corks should be softened by rolling 
them between two hard surfaces, as with the foot 
on the floor. They may be rendered much less 
pervious by soaking them in melted paraffine. -p I(J ^ Filter 

To Remove Sticking Glass Stoppers. — Strike Stand. 

the stopper gently with a piece of wood, or 
against a table, and if this fails to loosen it, heat the neck of the bottle 
by friction with a coarse string or in the flame of a lamp. The neck 
expands, and the stopper is generally loosened. If it still sticks, wedge 
two pieces of wood between the projecting part of the stopper and the 




MORTARS, EVAPORATORS, CRUCIBLES. 141 

mouth of the bottle, bind their ends together with wire to keep them in 
place, and invert the bottle in water. The swelling of the wood should 
force out the stopper. 

Cork-Borers. 
Cork-borers are hollow cylinders of brass or steel for making holes 



Fig. 53. — Cork-Borers. 
through corks to admit glass tubes. It is convenient to have a set of 
borers of different sizes. Cork-borers may be made of strong tin tubes 
with the edges soldered together by filing away the joint until it is of 
the same thickness as the other part of the tube, strengthening the tube 
by soldering to the outside of one end a short tin cylinder, and sharp- 
ening the other end. The borer is worked by means of a stout wire 
passed through holes in the end to be held in the hand. In using the 
cork-borer, the hole should not be cut entirely through the cork from 
one end, but should be bored from both ends. The end of a glass tube 
to be put through a cork, should be rounded by heating to redness and 
cooling, or else with a file or on a grindstone. 

Mortars, Eyaporators, Crucibles. 

A mortar is a vessel in which substances are pulverized with a pestle. 
Mortars are made of porcelain, iron, glass, or agate, the porcelain mortar 
being in most common use. A heavy tea-cup or bowl and wooden pestle 






Fig. 54. — Mortar and Fig. 55. — Evaporator. Fig. 56. — Cru- 
Pestle. cible. 

answer very well for pulverizing many substances. Some substances 
may be crushed with a knife-blade on a piece of glazed paper. Mortars 
for ordinary purposes should be about 3 inches in diameter. 

An evaporator is a shallow porcelain (usually) dish in which liquids 
are heated slowly. A convenient size is 4 oz. 

A crucible is a small vessel in which substances are heated intensely. 
Porcelain crucibles are used for ordinary purposes. Convenient sizes 
are | oz. and f oz. 



142 



APPARATUS. 



Glass Apparatus. 

Vessels in Which Liquids May be Heated.— Such vessels have very 
thin bottoms. 

Beakers are vessels with a flaring rim, having the form of an ordinary 
tumbler. They therefore stand 
upright without support, and their 
contents may be readily stirred. 
They are usually sold in sets of 
different sizes called nests. Con- 
venient sizes are 2, 3, and 5 oz. 

Test-tubes are long, cylindrical 
vessels, convenient for heating a 
small quantity of substances 
quickly. They are of various 
sizes ; for ordinary purposes they 
should be from 4 to 6 inches long 
and the opening small enough to 
be closed with the thumb. A few 
test-tubes of large size may be 
kept for receivers and generators. 
A test-tube rack is a wooden 
stand for supporting test-tubes. 
Its shelves either contain holes in 
which the tubes are placed erect 
(Fig. 59) or posts on which they 




Fig. 57. — Nest op 
Beakers. 



I rig. DJJ Or pOSIS on wiiiv.il mejr 

are inverted (Fig. 60). In an inverted position tubes quickly dry, and 
their inner sides are protected from dust. A test-tube holder is a con- 
trivance for holding a test-tube in the flame. It may consist of two 
pieces of wood, one of which is hinged to the other, and with a hole 
between the pieces at the free ends to receive the tube,, or of a strip of 




Fig. 59. — Test- Fig. 60. — Test-Tube 
Tube Rack. Rack. 



F g. 61. — Test-Tube 
Holder. 



several folds of paper placed around the tube. Test-tubes can generally 



GLASS APPARATUS. 



143 



be held bet-ween the thumb and fingers. A convenient test-tube cleaner 
is a short piece of rubber tubing on the end of a glass rod or tube. 




Fig. 62. — Flask. 




Fig. 63.— Retort. 



Flasks and Retorts. — Flasks are used for a great variety of purposes 
retorts are used mainly for certain kinds of distillation. 

2. Vessels to Contain Liquids and Gases. — Such vessels hav» 
thick walls. 

Bottles. — Bottles are either of clear or green glass, narrow or wide- 
mouthed, have either cork or glass stoppers. Liquid reagents should 
be kept in narrow-mouthed, glass-stoppered bottles of 6 to 8 oz. capac- 
ity. Dry reagents should be kept in wide-mouthed bottles of 1 to 2 oz. 
capacity. The bottle should be plainly labeled with the name and 
symbol or formula of the substance it contains. 

Receivers. — Receivers are of various forms. Wide-mouthed bottles of 
clear glass make very good receivers in which to collect and experiment 
with gases. Open-bottomed receivers may be made of bottles by cut- 




Fig. 64. — Receivers. 



Fig. 65. — Deflagrating Spoon. 



ting off the bottoms (p. 145) Convenient sizes are pint and quart receiv- 
ers. Glass cylinders are frequently used as receivers. 

A deflagrating spoon is an apparatus used for burning substances in 
gases. It consists of a small bowl-shaped vessel, to which is riveted a 
straight wire handle. 

Funnels. — Funnels of 2f and 3i inches in diameter are of convenient 
uzes for most purposes. The best angle for funnels for filtration is 60°. 




144 AIDS IN EXPERIMENTING. 

Glass and Rubber Tubing. 

Two varieties of glass tubing are used by the chemist, hard and soft. 
Hard tubing is very difficult to fuse ; it is used for tubes in which to 
heat intensely or ignite substances. Soft tubing readily softens in an 
alcohol or gas flame ; it is put to a great many uses by the chemist. 
A, Fig. 66, is a good size for hard, and B for soft glass 
tubing. 

Rubber or caoutchouc tubing is used for connecting 

glass tubes, for gas and liquid delivery tubes, etc. The 

66. — Sec- inner diameter of the rubber tube must be a little less 

tions op Glass than the outer diameter of the glass tubes which it is to 

connect. The ends of the glass tubes should be rounded 

in a flame to prevent sharp edges from cutting the rubber. 

Litmus Paper. 
Boil litmus with about six times its weight of water, and filter. Divide 
the filtrate into two parts; into one stir a few drops of a solution of 
so limn hydrate, and into the other hydrochloric acid, drop by drop, 
until the liquid just becomes distinctly red. Now dip strips of filter 
paper into the blue solution for blue paper, and others into the red solu- 
tion for red paper, and dry the strips by suspending them on threads. 
Litmus paper should be protected from light, and from fumes, etc., of 
the Laboratory. It may be well preserved between the leaves of a book. 

Aids in Experimenting, 

Glass-working. 

Cutting Glass. — The best instrument for cutting window or plate 
glass is the diamond, but as this is expensive, the wheel-cutter (kept at 
hardware stores), a small toothed steel wheel running in the end of an 
iron handle, answers the purpose very well. Disks may be cut by run- 
ning the cutter around a bottle or any other round object, or by fasten- 
ing it to one foot of a pair of compasses, the centre foot being kept from 
slipping by placing it on a bit of moistened stiff paper laid on the glass. 

Glass tubes are cut by means of a triangular file. Make a deep 
scratch in the tube with the file, one draw of which is generally suf- 
ficient. Then take the tube in the two hands, so placed that the thumbs 
are in contact on opposite sides of the scratch, and break it by pushing 
with the thumbs and pulling with the fingers. 

Tubes larger than about f of an inch in diameter cannot be cut by 
making a single scratch, but must be scratched all around ; and success 
is more certain if the file be wet with spirits of turpentine. Large tubes 



GLA SS- WORKING. 1 45 

may also be easily cut by the method for cutting bottles described in the 
next paragraph. 

Bottles are neatly and quickly cut by wrapping a long piece of twine 
once around them where the fracture is to be made, pulling the ends of 
the string backward and forward until the glass is quite hot, and then 
quickly plunging the bottle into water. 

The bottle may be held firmly and the string kept in place by a simple 
device. A V-shaped opening, like that of a bootjack, is made in a thick 
pine board about 12 inches by 8, and a piece broad enough to admit the 
string is cut out of the V end between the sides of the board. The 
board is clamped in a vise or screwed to a table, and one person holds 
the bottle in the opening while two others pull the string. 

Boring Glass. — A drill for boring small holes in glass may be 
made by grinding the hard end of a triangular file to a triangular point. 
First make a scratch where the hole is to be made ; then work the drill 
into the glass, keeping it constantly wet with spirits of turpentine, until 
the hole is through. Care must be taken in enlarging the hole after 
the drill is through, as the glass is liable to crack. The drill should be 
kept sharp by frequent grinding. 

A drill for boring large holes is made of a copper tube by filing saw- 
teeth in one end. Clamp a block of wood containing a hole, in which 
the drill will easily turn, against the glass, put emery powder and water 
in the hole and rotate the drill in it, pressing toward the glass. Keep 
the end of the drill well supplied with emery and water. 

Grinding Glass. — Glass is easily ground by rubbing it over an 
iron plate in wet sand. Any plate with an even surface, as a stove 
disk, answers the purpose. For very accurate grinding a piece of plate 
glass and emery-powder (which are kept at hardware stores) are 
necessary. 

Bending Glass Tubes. — Place the tube in the flame so that the 
section to be bent is just above the extremity of the blue cone, the hot- 
test part of the flame ; move it backward and forward a few times in 
the direction of its length to prevent breaking by the sudden expansion 
of the glass, and then, holding one end fixed in the left hand, press with 
the forefinger of the right hand gently upward. The tube will soon 
begin to bend, and when bent a little, change its position slightly to the 
right or left, so as to heat it in a new place, pressing upward until it 
bends a little, as before. Continue this until the required bend is made. 

Sealing Tubes. — Hold a piece of glass against the end of the 
tube to be sealed, in a blow-pipe flame, until the pieces are smelted to- 
gether ; then heat the tube near the joint, and when sufficiently hot, 
pull a little of the end off with the piece of glass. Hold the pointed 
1 



14G 



AIDS IN EXPERIMENTING. 



Fig. 67, 



-Drawn-out Tube, Jet 
Tube. 



Fig. 68. — Platinum Wire with 
Han hi.K. 



end a short time in the flame to give it a rounded form. Small-sized 
tubes may be neatly sealed by holding the end in a blow-pipe flame until 
the opening closes by contraction. 

Drawing Out Tubes. — Hold the tube between the thumb and 
first two fingers of each hand in a 
^^^Z—-^. s3l blow-pipe flame, rotating it constantly 
until it becomes sufficiently soft to 
bend easily. Then quickly remove 
it from the flame and draw the ends 
apart, continuing the rotary motion, 
until the diameter has been suf- 
ciently reduced. The conical sec- 
tions formed by drawing the tube should taper symmetrically. By 
drawing the sections so far apart as to disconnect them and breaking 
off the tine points, jet tubes for burning hydrogen, etc., are produced. 
Platinum wires for flame testing should have glass handles, which 
may be attached to them as follows : 
Draw off the end of a piece of tubing 
2 or 3 inches long, break off the fine 
point, insert one end of the wire in 
the opening, and hold the end of the 
fube containing the wire in the flame. The wire and glass w r ill smelt 
together. 

Piercing the Side op a Tube. — Direct a small pointed blow- 
pipe flame against the tube where it is to be pierced, at the same time 
closing one end with a finger and pressing against the air in the tube 
with the mouth over the other end. The glass, when sufficiently hot, 
yields to the pressure and a hole is made. Flasks, test-tubes, etc., may 
be pierced in the same manner. 

Blowing Bulbs. — Seal a tube several inches long, and heat the 
sealed end, continually rotating the tube, 
until it is red hot ; then, quickly placing the 
cold end in the mouth, compress the air in 
the tube, and the heated end will form into 
a bulb. 

Fusing Tubes Together. — If the tubes 
are not of the same diameter, heat the Fig. 69. — Glass Bulb. 
end of the smaller one and enlarge it with the end of a file to the size 
of the larger one. Then hold the ends to be fused together in the flame, 
not allowing them to touch each other, rotate slowly, and when they 
are quite soft, remove them from the flame and push them together. 
To reduce the thickened joint, close one end of the tube, rotate the 




SOLDERIXG. 147 

joint in the flame, and when sufficiently soft, enlarge it slightly by 
blowing. Compress it by heating, then blow out again, and repeat 
these operations until the thickening disappears. 

Soldering-. 

In soldering, a substance is used to cleanse the surfaces to be united, 
and an alloy to unite them and form a rigid joint. Light articles can 
be soldered by means of an alcohol or gas flame. 

In soft soldering a concentrated solution of zinc chloride is generally 
used for cleansing the surfaces. To prepare this, put 2 or 3 g. of sheet 
zinc, cut into small pieces, in a test-tube, add 10 c.c. of hydrochloric 
acid, and heat until the action of the acid on the metal has ceased. 
The solution (zinc chloride) is called soldering fluid. The alloy used, 
called solder, consists of lead and tin. Common worn-out pewter spoons 
and tin-foil are good substitutes for solder. 

Brighten the surfaces to be united, wet them with soldering fluid, and 
clamp them together with a piece of solder between ; then heat the 
joint in a bloAv-pipe flame. Direct the flame against the metals to be 
united, and allow them to melt the solder. When the solder has spread 
between the surfaces, wet the joint with water, and the metals will be 
found firmly united. 

In hard soldering borax is generally used for cleansing the surfaces, 
and a good solder for many articles is silver coin, prepared by hammer- 
ing a small coin into a thin plate and cutting this into small pieces. 

Brighten the surfaces to be united, fit them to each other, and clamp 
them together. Then moisten the joint with water, and sprinkle it with 
some pulverized borax ; next add the solder, and cover this with borax. 
Now heat in a blow-pipe flame gently until the borax has ceased to 
swell, and then intensely until the solder flows between the surfaces. A 
malleable joint is made by this process. 



APPARATUS AND MATERIAL. 



Apparatus required in making the experiments in this book once: 

1 



3 Beakers, 2. 3 and 6 oz. 
l Beaker, tall, 8 oz. 

1 Blow-pipe (brass). 

2 Bottles, wide-mouthed, quart. 

3 " l - " pint. 

2 " " " %pint. 

2 Crucibles, porcelain. % and % oz. 
1 Evaporator, porcelain, 4 oz. 
1 Filter stand. 

1 Flask, 8oz. 
•2 Flasks. 4oz. 

2 Funnels, 2 and 4 oz. 

1 Funnel tube (small), 
l Triangular file. 

1 (.lass rod. 6 in. long. 

2 feet glass tubing, size of a quill. 

1 Glass tube about iy ft. long and 1 

in. in diameter. 
1 Lamp for alcohol or gas. 
1 Pneumatic trough, about 10x6x4 in. 
l pair Pincettes (Forceps) steel. 



Platinum wire, 3 in. long. 
Receiver, stoppered, quart. 

" " pint. 

tk " X A pint. 

Retort, glass stoppered, pint. 
" " " 4 oz. 

Retort stand. 

Rubber cork to fit wide-m. pint 
bottles. 
Rubber cork to fit large test-tubes. 

" " " small flask. 

feet vulcanized rubber tubing 
adapted to the glass tubing. 
Test-tubes, 8 in. long. 

" 6 in. '• 

" 4 in. " 

Test-tube rack for 12 tubes, 
wire Triangle, 
small Watch glasses, 
or 6 ft. of stout iron wire, 
square of fine wire gauze. 3^x3* in. 



Chemicals, etc., required in making the experiments in this book once: 



Acid, Acetic, \4 oz. 

Hydrochloric, y lb. 
N itric, l 4 lb. 
Sulphuric, Yz lb. 
Alcohol, 2 oz. 
Alum, y oz. 
Ammonia water, J4 lb. 
Ammonium chloride, y oz. 

" nitrate, y oz - 

Aniline red, granule. " 
Antimony. 10 grains. 
Arsenions oxide, 5 grains. 
Barium chloride, 5 grains. 

" nitrate, 30 grains. 
Beeswax, y oz - 
Benzene (Benzol) y oz - 
Bleaching powder, 2 oz. 
Blue vitriol. ^ oz. 
Borax, 10 grains. 
Calcium chloride. 1 oz. 
Carbon disulphide, y oz. 
Charcoal, animal, 1 oz. 

" common, several pieces. 
Cloves, ground, 1 oz. 
Cobaltous chloride, 5 grains. 
Copper wire, y oz. 

" filings, y, oz. 
Ether, % oz. 
Fluor spar, y oz. 
Ferrous sulphide, 10 grains. 
Glauber's salt, y oz. 
Glycerine, y 2 oz - 
Gold leaf, sq. inch. 
Green vitriol, y oz. 
Gun cotton, 5 grains, 
iron filings, y oz. 
L ad acetate, % oz. 



| Litharge, 10 grains. 
Litmus, 10 grains. 

paper, 1 sheet of each color. 
Logwood extract, 15 grains. 
Magnesium ribbon, 3 in. 

" carbonate, 5 grains, 

sulphate, 5 grains. 
Manganese dioxide, 1 oz. 
Mercuric chloride, 5 grains. 
Mercury, y oz. 

" cyanide, 5 grains. 
Nut galls, y oz. 
Oxalic acid, 30 grains. 
Phosphorus, 10 grains. 
Piano wire, fine, y oz. 
Potassium, 5 grains. 

'* bromide, 2 grains. 

" iodide, 2 grains. 

" carbonate, y oz. 

chlorate, y oz. 
" dichromate, 5 grains. 

" ferreo cyanide, 10 grains. 

" hydrate (in sticks) \y oz. 

" nitrate, y oz. 

Shellac, 15 grains. 
Silver chloride, 5 grains. 

" nitrate, 5 grains. 
Sodium, 5 grains. 

" acetate, 5 grains. 
" carbonate, y oz. 
" hydrate (in sticks) y oz. 
Strontium nitrate, 30 grains. 
Sulphur, flowers of, y oz. 

roll, y lb. 
Turpentine, 1 oz. 

" oil of, 1 oz. 

Zinc. 2 oz. 



(148) 



INDEX. 



[Figures refer to Pages.] 



Acetates, US. 
Acid, acetic. 118. 

arsenious. 81. 

boric (boraeic). 84. 

carbolic, 110. 

citric, 119. 

gallo-tannic, 119. 

hydrochloric, 41. 

hydrocyanic, 103. 

hydrofluoric, 43. 

malic, 119. 

muriatic, 41. 

nitric, 74. 

oxalic, 118. 

prussic, 103. 

pyroligneous, 118. 

salicylic, 119. 

sulphuric, 55. 

sulphurous, 53. 

tannic, 119. 

tartaric. 119. 
Acids, bases, and salts, 9. 
Air, 76. 
Alabaster, 60. 
Albumen, 120. 
Albuminoids, 120. 
Alcoholic liquors, 115. 
Alcohols, 112. 
Aldehydes, 113. 
Alizarin, 123. 
Alkali, del", of, 17. 
Alkaloids, 120. 
Allotropism, def. of, 18. 
Alloy, def. of, 19. 
Alum, 65. 

chrome, 91. 
Aluminum, 64. 

hydrate, 64. 

ox.ide, 64. 

silicate, 65. 

sulphate, 65. 
Amalgam, 19. 
Amber, 111. 
Ammonia, 70. 

water, 70. 
Ammonium, 70. 

carbonate, 72. 

chloride, 72. 

nitrate, 72. 
Am or phis m, 17. 
Amorphous carbon, 93. 
Ampere's law, 16. 
Amylose, 114. 
Analysis, 9. 
Aniline, 109. 
Antimony, 82. 
Apparatus and material, 148. 



Aqua ammonia, 70. 

fortis, 74. 

regia, 43. 
Aromatic compounds, 109. 
Arsenic, 80. 

trioxide, 81. 

sulphides, 82. 
Arsenious acid, 81. 

oxide, 81. 
Asphalt. 111. 
Mom, def. of, 8. 
Atomic theory, 8. 

weights, 15. 
Auric chloride, 84. 

Balance and weights, 132. 
Balsams. 111. 
Barium, 60. 
Barlev sugar, 113. 
Bases'; 9. 
Beakers, 142. 
Beer, 115. 
Bell metal, 66. 
Benzene (benzol), 109. 
Benzine, 109. 
Beryllium, 66. 
Bessemer converter, 90. 
Binary compounds, 13. 
Bismuth, 82. 
Black lead, 93. 
Blast furnace, 87. 
Bleaching powder, 59. 
Blowers, 136. 
Blow-pipes. 135. 
Bond symbols, 14. 
Bone ash, 95, 

black, 95. 
Borax, 84. 

Boric (boraeic) acid, 84. 
Boron, 84. 
Bottles, 143. 
Brandy, 116. 
Brass, 66. 
Brazil wood, 123. 
Bromine, 44. 
Butter, 122. 

Cadmium, 64. 
Caesium. 35. 
Caffeine, 120. 
Calcium, 58. 

carbonate, 59. 

chloride, 59. 

hydrate, 59. 

oxide, 5S. 

phosphate, 60. 

sulphate, 60. 



(149) 



150 



JXDEX. 



Calomel. 68. 

Camphors and resins, ill. 
Caoutchouc, ill. 
Caramel, 113. 

Carbhydrates, 113. 
Carbolic acid, 110. 
Carbon. 92. 

dioxide, 97. 

disulphide, 103. 

monoxide, 96. 
Carbonic acid, ( J7. 

oxide, 96. 
Casein, 12L 
Catalysis, 18. 
Caustic potash, 33. 

soda. 30. 
Celluloid, 117. 
Cellulose. 117. 
Cerium, 04. 
Cinnabar, 68. 
Charcoal. 93. 

animal. 95. 
Chemical action. 12. 

affinity, 12. 

combination, laws of, 14. 

compound, def. of, 9. 

element, del*, of, 9. 

terms, 17. 

processes, 19. 
Chemistry, def. of, 8 
Chloral. 113. 
Chloride of lime. 69 
Chlorides, n. 
Chlorine. 38. 
Chloroform, 108. 
Chrome alum. 91. 
Chromium, 91. 
Citric acid, 119. 
Coal gas, '."J. 

tar, 96. 
Cobalt. 90. 

( lobaltOUS chloride. 1)1. 
Cochineal, 123. 
Coke. 95. 
Collodion, 117. 
Coloring substances, 123. 
Columbium, 69. 
Combustion, 100. 
Compressors, 138. 
Copper 

acetate, 07. 

oxides, 07. 

sulphate, 67. 
Copperas, 88. 
Corrosive sublimate, 08. 
Cork-borers, 111. 
Corundum. 64. 
Cosmoline, 108. 
Cream of tartar, 119. 
Crucibles. 141. 
Crystallization. 20. 

water of, 18. 
Cyanides. 103. 
Cyanogen, 103. 

Decipium. 10. 
Definite proportions, 14. 
Definitions, 8. 
Deflagrating spoon, 143. 
Deliquescence. 18. 



Dextrine. 116. 
Diamond, 92. 
Didymium, 04. 
Distillation, 21. 
Distilled liquors, 116. 
Distilling apparatus. 27 
Dyad, 14. 
Dyeing. 123. 
Dynamite, 122. 

Effervescence, 18. 
Efflorescence, 19. 
Elements, names of, 12. 

symbols of, 12. 

table of, 10. 
Emery. 64. 
Epsom salt, 63. 
Erbium, 10. 
Essential oils. 110. 
Etching on glass, 44. 
'• •• brass, 75. 
Ethers. 112. 
Ethyl alcohol, 112. 
Ethylene. 109. 
Evaporators, 141. 

Eats axd fixed oils, 121. 
Fermentation, 115. 
Fermented liquors, 115. 
Fibrin, 121. 

Filtering apparatus, 140. 
Filtration, 21. 
Eire damp, 107. 
Flames, blowpipe, 102. 
Flasks, 143. 
Fluorine, 43. 

etching with, 44. 
Fluor spar. 43. 
Forma 

Gallium. 04. 
Gas carbon. 96. 

generator, 23. 

holders. 137. 
Gelatin. 121. 
German silver, 66. 
Glass. 104. 

working, 144. 
Glauber's salt, 31. 
Grlucinum, 64. 
Glucose. 114. 
Glue, 121. 
Gluten. 121. 
Glycerine, 122. 
Gold, 83. 

Graphic symbols, 14. 
Graphite, 93. 
Group, aluminum, 64. 

calcium, 58. 

carbon, '92. 

chlorine, 38. 

chromium, 91. 

copper, 00. 

gold, 83. 

iron, 85. 

magnesium, 62. 

nitrogen, 69. 

oxygen, 45. 

platinum. 91. 

sodium, 20. 



-par. 43 
he, 13. 



IXBEX. 



151 



Gum arable, 117. 
Gums. 117. 
G iui cotton, 117. 
Gunpowder, 34. 
Gutta percha, 111. 
Gypsum, 60. 

Hartshorn, 71. 
Heating on charcoal, 22. 

Historical sketch, 7. 
Holmium. 10. 
Hydrate, def. of, 17. 
Hydraulic mining, 84. 
Hydrocarbons and. derivatives. 
Hydrochloric acid, 41. 
Hydrocyanic acid, 103. 
Hydrofluoric acid, 43. 
Hydrogen, 23. 

arsenide, 80. 

dioxide. 28. 

phosphide, 79. 

sulphide, 52. 

IXDIGO, 123. 

Indium, 92. 

Inorganic chemistry, 23. 

Iodine, 44. 

Iridium, 92. 

Iron, 85. 

hydrate, 88. 

oxides, 88. 

sulphates, 88. 

sulphides,' 88. 
Isinglass, 121. 
Isomerism, 18. 

Kerosexe, 108. 

Lampblack, 95. 
Lamps, 134. 
Lanthanum, 10 
Laughing gas. 73. 
Law of volumes, 17. 
Lead. 61. 

acetate, 61. 

dioxide, 61. 

monoxide, 61. 

silicate, 61. 

sulphide, 61. 
Leblanc's process, 32. 
Lime, 58. 
Limestone. 59. 
Linseed oil, 122. 
Litharge, 61. 
Lithium, 35. 
Litmus, 123. 

paper, 144. 
Logwood, 123. 
Lunar caustic, 37. 

Madder, 123. 
Magnesia, 62. 
Magnesium, 62. 

carbonate, 62. 

oxide, 62. 

sulphate, 63. 
Malic acid, 119. 
Manganese, 90. 

dioxide, 90. 
Marble, 59. 



Marsh gas, 107. 
Marsh's test, 81. 
Matches. 79. 
Matter, def. of, 8. 

units of, 8. 

properties of, 8. 
Mercuric chloride, 68. 
Mercurous chloride, 68. 
Mercury, 68. 
Methane, 107. 
Methyl alcohol, 112. 
Metric measures, 133. 
Mineral coal, 96. 
Mixture, def. of, 9. 
Molecule, def. of, 8. 
Molvbdenum, 91. 
Moiiad. 14. 
Mordant. 123. 
Morphine, 120. 
Mortars. 141. 
Mother liquor, 18. 
Multiple proportions, 15. 
Muriatic acid, 41. 

Nascext state, 18. 
Nickel, 90. 
Nicotine, 120. 
N itrates, 74. 
Nitre, 34. 
Nitric acid, 74. 
Nitric oxide, 74. 
Nitro-benzene, 109. 
Nitrogen, 69. 

dioxide, 74. 

monoxide. 73. 

tetroxide, 74. 
N itro-glycerine, 122. 
Nomenclature and notation, 12. 
Norwegium, 11. 

Oil op vitriol, 55. 

Olefiant gas, 109. 

defines, 109. 

Organic chemistry, 107. 

Osmium, 92. 

Oxalic acid, 118. 

Oxide, def. of, 46. 

Oxygen. 46. 

Oxy-hydrogen blow-pipe, 50. 

flame, 50. 
Ozone, 49. 

Palladium, 92. 

Paraffines, 107. 

Parchment paper. 117. 

Pearl ash, 34. 

Pepsin, 121. 

Percentage composition, 15. 

Petroleum, 108. 

Pewter, 61. 

Phenol, 110. 

Phosphorus, 77. 

oxides and acids, SO. 
Pincettes. 139. 
Plaster of Paris, 60. 
Platinum, 91. 

black, 92. 

sponge, 92. 
Plumbago, 93. 
Pneumatic trough, 136. 



|52 INDEX. 

Potassium, 33. 

bromide, 33. 

carbonate, 34. 

chlorate, 34. 

chloride, 33. 

cyanide, 34. 

hydrate, 33. 

hydrogen carbonate, 34. 

iodide, 33. 

nitrate, 34. 

permanganate, 00. 
Practical questions, 28, 37. 57, 106. 
Precipitation, 21. 
Proof spirit 112. 
Prussic acid, 103. 
Prussian blue B9. 
Puddling furnace, 86. 
Pyroligneoua acid, 118. 

Q A NT I VALENCE, 15. 

Questions, 125. 
Quick lime, 58. 
Quinine. 120. 

Radical, def. of, 9. 
React ion. del. ot, 19. 
Receivers, 1 13. 
Red precipitate, 68. 
Resins, ill. 

Kelolls. 143. 

Retort stand. 139. 
Reverberatory furnace, 32. 
Rhodium, 91. 
Rochelle powders, 119. 

salt. 111). 
Rougt 

Rubidium, n. 
Ruthenium, 91. 

Safety lamp. 102. 
sal ammoniac, 72. 
Saleratus, 34. 
Salicylic acid, ill). 
.Salts! 0. 
Scandium, 11. 
Selenium, 57. 
Silica, 103. 
Silicon, 103. 

dioxide, 103. 
Silver. 36. 

chloride, 36. 

nitrate, 36. 
Soap, 122. 
Sodium, 20. 

biborate, 32. 

carbonate, 31. 

chloride, 30. 

hydrate, 30. 

hydrogen carbonate, 32. 

nitrate, 32. 

silicate, 104. 

sulphate, 31. 
Solder, 61. 
Soldering. 147. 
Solution, def. of, 19. 
Specific gravity, 22. 

volumes, 17. 
Starch, 116. 
Steel, 89. 
Stoppers, 140. 



Strontium, 60. 
Strychnine. 120. 
Student lamp, 100. 
Substance, def. of, 8. 
Sucrose, 113. 
Sugars, 113. 
Sulphates, 55. 
Sulphides. 51. 
Sulphur, 51. 

dioxide, 53. 

trioxide, 54. 
Sulphuretted hydrogen, 52. 
Sulphuric acid, 55. 
Sulphurous acid, 53. 
Symbols, 12. 

bond. 14. 

graphic, 14. 4 

Table op elements, 10. 
Tannic acid, 110. 
Tantalum, 69. 
Tartar emetic. 119. 
Tartaric acid, 119. 
Tellurium. 57. 
Terbium, 11. 
Test tubes. 142. 
Test tube holder, 142. 

rack. 142. 
Thallium. Ho. 
Theine, 120. 
Thermometers, 134. 
Thorium, 11. 
Thulium, 11. 
Tin, 105. 

compounds, 106. 
Titanium, 106. 
Tubing. 144. 
Tungsten, 91. 
Turpentine, 110. 

oil of, 110. 
Type-metal, 61. 

Unit volume, 17. 
Uranium, 83. 

Vaxadium, 83. 
Verdigris, 67. 
Vinegar, 118. 
Vitriol, blue. 67. 

green, 88. 

white, 64. 
Volume relations, 16. 
Vulcanized rubber, 111. 

Water, 26. 

of crystallization, 18. 

glass, 104. 
Whiskey, 116. 
White lead, 62. 
Wine, 115. 
Wolf'ramium, 11. 

Ytterbium, 11. 
Yttrium, 11. 

Zinc, 63. 

chloride, 64. 

oxide, 64. 

sulphate, 04. 
Zirconium, 106. 



